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Thread: 12-2 with ground for multi wire
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09-23-2011, 06:25 PM #1
12-2 with ground for multi wire
OK. I think what I am seeing in this service panel is 12-2 Romex with ground being utilized for multi-wire circuits! The sure-test showed no false grounds for what that is worth.
multiwire.jpg
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09-23-2011, 07:09 PM #2
Re: 12-2 with ground for multi wire
Its possible they're feeding a 240v circuit with two single pole breakers(un-tied and incorrect).
Were you able to determine where the conductors went after they left the panel?
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09-23-2011, 07:34 PM #3
Re: 12-2 with ground for multi wire
Very limited labeling and I didn't follow up on the labels. All were for 110 volt circuits. I also didn't do the arithmetic to see what wiring was on what phase. I figured the electrician could sort that out. Have to say, this was first in 15 years!
Of course, the client asked, "how do you fix this?". I said, "I don't, you need an electrician."
Last edited by Benjamin Thompson; 09-24-2011 at 04:12 AM.
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09-23-2011, 08:52 PM #4
Re: 12-2 with ground for multi wire
I'm not sure how you are seeing MWBC. The black and white wires connected to the single poles would mean they are using the bare equipment grounds in those nm cables as neutral if that were the case.
A picture that has more clarity would be nice.
I always cringe when I see Murray metering equipment as those main breakers are more apt to fail than any breaker I've ever experienced.
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09-23-2011, 09:31 PM #5
Re: 12-2 with ground for multi wire
You're right, this panel is wired with each romex cable, servicing two circuits, and using the single ground lead, as the neutral for two circuits. The NEC requires a neutral equal to the phase conductor, and therefore, two circuits cannot share a neutral lead. It is very obvious this was a non professional installation, and was not inspected. It also was done AFTER the utility co connected the meter. Of course, this also means the previous branch circuits were pulled out, and replaced with what is there now.
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09-24-2011, 02:47 PM #6
Re: 12-2 with ground for multi wire
Did you confirm they were multiwire branch circuits by using a clamp-on ammeter to measure the current on the grounds and the two hots within the NM cables you suspect were multiwire circuits? You could easily confirm if they were multiwire circuits with a clamp-on ammeter (a tool every home inspector should have in their tool bag, but a tool which does not always get a lot of use - just like having a multimeter in your bag, you should have it, but you likely will not use it often).
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09-24-2011, 05:46 PM #7
Re: 12-2 with ground for multi wire
I didn't. Do you have an alternate theory for this configuration?
Maybe this photo is clearer
panel2.jpg
Last edited by Benjamin Thompson; 09-24-2011 at 06:02 PM.
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09-24-2011, 06:04 PM #8
Re: 12-2 with ground for multi wire
With the information you have given, I do not have an alternate theory, nor am I convinced you are correct. I am leaning toward you being correct, but there is not enough information to know for sure.
As a home inspector you would not want to do any of the things which may be needed to confirm those are multiwire branch circuits ... other than having used a clamp-on ammeter to check the amps in the two hots and the ground for each NM cable.
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09-24-2011, 08:34 PM #9
Re: 12-2 with ground for multi wire
What is your logic that the circuits are MWBC ? Their is no way to tell for sure without testing. I wanted the clearer picture to determine the wiring (blacks and whites) was originating from the same nm cable.
You could have turned off both breakers of one circuit in question ... found what stopped operating and that would tell you if a 120 volt load was on the circuit or a 240 volt load.
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09-24-2011, 09:36 PM #10
Re: 12-2 with ground for multi wire
Well Roger, I count (11) 110 volt breakers and (5) 220 volt. (2) 110 volt with white wires. How many 1200 sqft homes have you seen with (7) 220 volt circuits and and (7) 110 volt circuits? BTW, electric furnace, not baseboard heat.
1 220 for the dryer
1 220 for the water heater
2 220 for the furnace
1 200 for the range
What would the other (2) 220 circuits be for? And why wouldn't they be on 2 pole breakers?
And you can see very well in the photo that the black and white originate from the same NM wires.
I "could" have done alot of things, but I didn't need to, it was clear to me what was going on. I surprised it isn't clear to you.
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09-25-2011, 05:33 AM #11
Re: 12-2 with ground for multi wire
Help me here, please. When did we return to 110/220 voltages?
I thought we are at 120/240 VAC here in the U.S.
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09-25-2011, 06:55 AM #12
Re: 12-2 with ground for multi wire
Possiblities,
Air Conditioning...Central split or receptacle; 120/240V circuits or straight 240vac (250V rated receptacles);
Split cooking facilities, i.e. electric cooktop and wall oven(s);
120/240V MWBC or feeder to garage or detached accessory bldg, "hot tub", pool heater, etc.;
in-floor electric radiant in sunroom, entry, bathroom, etc.;
Sewage ejectors/lift pumps; well pumps.
See what appears to be some older UF landing to the left bottom most breaker and the right top most breaker, hopefully an illusion; some reidentification lower right, appears to be arc ghosting and melt down center lower left, excessive debris, unsecured/clamped cables, and excessive cable sheath & cable insulation present, and over-stripped (exposed conductors) insulation at left. As you indicate the directory is less-than-complete or accurate, obvious referral required. 5 ea. different type mount.
Suspect flash, arc, short, fire, and/or lightening incident(s).
7 or more 120/240 and/or 240V branch circuits and/or feeders wouldn't be the least bit unusual for all-electric home of that size.
Last edited by H.G. Watson, Sr.; 09-25-2011 at 07:31 AM.
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09-25-2011, 12:10 PM #13
Re: 12-2 with ground for multi wire
There could be ceiling heat strips, or window air conditioner outlets to account for all the 240V circuits.
It took some zooming in, but I finally could see the white wires going to single pole breakers. Did you pull off any outlet covers to see what kind of wiring was there?
Last edited by Jack Feldmann; 09-25-2011 at 12:16 PM.
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09-25-2011, 09:03 PM #14
Re: 12-2 with ground for multi wire
Well Roger, I count (11) 110 volt breakers and (5) 220 volt. (2) 110 volt with white wires. How many 1200 sqft homes have you seen with (7) 220 volt circuits and and (7) 110 volt circuits? BTW, electric furnace, not baseboard heat
What would the other (2) 220 circuits be for? And why wouldn't they be on 2 pole breakers?
Answer to second question ... that's a mystery that I thought you were trying to get us to help you answer.
And you can see very well in the photo that the black and white originate from the same NM wires
Nope I can't see it clearly. But I'll take your word for it. I asked the question for two reasons ... to see if they were paired with the correct black wire of the same cable assembly and to then determine if the white and black were connected to breakers on opposite hot legs of the service. This would be fundamental if you were trying to determine if MWBC was the wiring design. Black and white connected to breakers on opposite legs would signal 240 volt branch circuit not MWBC.
I "could" have done alot of things, but I didn't need to, it was clear to me what was going on. I surprised it isn't clear to you.
You have provided a picture and that is it. From that picture how can you possibly expect us to agree with you that those are MWBC ... ??? If the picture is that clear can you tell me the position/space the breakers that have white wires connected to them are on opposite hot legs from the black wires of the same cable.
I'm asking because if the person that did this knew to use opposite hot legs to correctly wire 240 volt or MWBC 120/240 then they would have known that using the equipment ground as neutral was a big no..no. I just doubt that this person would go around to all the outlets that are typically served by MWBC wiring a bare equipment ground to all the neutral terminals.
No offense but you didn't cover your bases as you should have before asking your question here ....
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09-26-2011, 05:27 AM #15
Re: 12-2 with ground for multi wire
Jerry:
Based on the emphasis added in your quote, it sounds like a clamp-on ampmeter should be a tool that all inspectors should be using. Do you feel that any of the published Standards of Practice or State Regulations require this or is this your opinion from your experience as a litigation consultant?
Gary Bottomley
Cadillac, Michigan
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09-26-2011, 06:37 AM #16
Re: 12-2 with ground for multi wire
The theory regarding baseboard heat could be possible, however; the one clear branch circuit that I can definitively trace visually reveals a black wire connected to circuit 24 and a white wire from the same cable assembly connected to circuit 17. If these are 120v circuits, the ground must be being utilized as a neutral. Since c/b 17 is an "A" phase and c/b 24 is a "B" phase, I guess they understood the concept of "additive" vs.
"phased." LOL. I am visually seeing the bare copper conductors connected to the panel case. (Do you think they bothered to scrape the paint to provide a good connection to the metal?) I can't think of a circumstance where the picture as provided reveals correct electrical wiring technique. Definitley requires evaluation by a professional.
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09-26-2011, 01:50 PM #17
Re: 12-2 with ground for multi wire
Gary,
I can't answer for Jerry, but I don't think any Standards of Practice call out the requirement for ANY tools.
I have a clamp on meter, but probably don't use it more than a half dozen times a year. Same with a multimeter.
Sometimes you have to go a little beyond normal so you don't look like a fool calling out something that is actually OK, or to call out something that is not all that obvious as a problem.
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09-26-2011, 03:00 PM #18
Re: 12-2 with ground for multi wire
Nope, and none of the SoP require flashlights, ladders, screwdrivers, pliers, moisture meters, receptacle outlet testers, etc.
... or is this your opinion from your experience as a litigation consultant?
Just like in this thread, there simply had not been enough information given to reasonably judge whether or not those breakers are multiwire branch circuits (they could be) or just 240 circuits with the white being used as hots (they could be), and what the home inspector writes up in the report depends on which they reasonably determine those to be.
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09-26-2011, 03:44 PM #19
Re: 12-2 with ground for multi wire
Help me please, I just do not understand why this question is still being bandied around.
By code, Current carrying conductors must be insulated, correct? The EGC can be bare, correct?
To be a multi-wire circuit, there can only be 120 VAC between the Ungrounded Conductor and the Grounded Conductor, Correct.
The grounded conductor cannot be used as an ungrounded conductor in a multi-wire circuit, Correct!
No ungrounded conductor can be used as a Neutral conductor.
If the panel in question is using 12/2 (arbitrary cable size) by code definition it cannot be used as a multi-wire branch circuit.
Either write the panelboard up for violating code, or have the homeowner or electrician prove to you that these are Not multi-wire branch circuits and let this item die a natural death.
Don
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09-26-2011, 06:02 PM #20
Re: 12-2 with ground for multi wire
INCORRECT! (Think about it first, then read on. )
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. (see phrase between the **)
"The grounded conductor *is not allowed to* be used as an ungrounded conductor in a multi-wire circuit,"
No ungrounded conductor can be used as a Neutral conductor.
If the panel in question is using 12/2 (arbitrary cable size) by code definition it cannot be used as a multi-wire branch circuit.
Which leaves us with the possibility that those are multiwire branch circuits ... and possibly not.
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09-26-2011, 06:07 PM #21
Re: 12-2 with ground for multi wire
Some of those grounding conductors appear to be undersized.
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09-26-2011, 06:08 PM #22
Re: 12-2 with ground for multi wire
Exactly! Thank you Don!
I think others (like me) that have not seen this before are trying to come up with alternative explanations, but so far, no one can.
The theories of additional 240 (OK, not 220) volt circuits don't hold water in this home.
I basically posted this as "informational" to let other home inspectors know about something to look out for. As Mr. Frazee pointed out, this is not readily evident from the pics or from observing the panel but is a serious safety hazard as the entire grounding system is energized.
That others don't see it as an issue perplexes me.
I would have tried the ammeter approach if I had thought of it, I carry 2 in the truck but would have somehow had to make sure those circuits were energized. As far as dismanteling outlets, I'm not going there.
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09-26-2011, 08:51 PM #23
Re: 12-2 with ground for multi wire
It never hurts to carry around a lamp socket that plugs directly into a receptacle that has a flasher button and a lamp as large as the flasher will handle. Makes it easy to see which breaker feeds a receptacle with an amp clamp - and in this case easy to verify if any of these circuits feed 120 volt loads
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09-26-2011, 10:06 PM #24
Re: 12-2 with ground for multi wire
First of all, there are plenty of reasons to call for an electrician to make repairs here. I think we would all agree there. Nobody is saying there is no cause for concern.
We are not all completely convinced that the bare conductors are being used as neutrals, as there are other explanations, which you've already seen.
What is the explanation for the presence of grounding, if the bare conductors are being used as neutrals? The homeowner added bootleg jumpers to every receptacle?
Is it possible that red wires, indicating 12/3 conductors, were used as neutrals on some of those circuits? I see 8 or 9 insulated neutral conductors going to the neutral bus, several are a reddish brown color. That's enough neutrals to supply the 120 volt circuits on the left side of the panel. The two 30 amps on the top of the left side look like a 240 circuit missing a tie-bar.
Most of the breakers on the right side of the panel, with the tie-bars, appear to be supplying 240 volt circuits, some of which may be capped off for future heating circuits. Sorry, but that is what I see there.
John Kogel, RHI, BC HI Lic #47455
www.allsafehome.ca
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09-27-2011, 05:10 PM #25
Re: 12-2 with ground for multi wire
There easily could be a 240 recep anywhere. It can be one thats easily mistaken too. Look at the picture. It's a 240v recep that fits into any place you would normally see a 120v unit. Look closely you'll see the hot slot is sideways.
I have one of these in my back porch (converted to small shop) to run an air compressor.
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09-27-2011, 08:39 PM #26
Re: 12-2 with ground for multi wire
Well, this is my last response on this topic. It reminds me of the stories about the native Americans actually not being able to physically see the ships of the pilgrims because it wasn't in their realm of experience or possibility!
Yes, I've only been doing this for 14 years and I wouldn't possibly know what is a 240 volt outlet and what isn't. I wouldn't know if there was radiant ceiling heat, I wouldn't know if some breakers were not in use,
Thank goodness for the buyer it was me inspecting the home and not one of you, telling them there may be no problem, "there are probably just some 240 volt circuits I haven't found that do not have handle ties and may not be on the same phase, but don't worry about it!"
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09-28-2011, 05:40 AM #27
Re: 12-2 with ground for multi wire
Ben,
Since you have been in the field for 14 years and have lost all knowledge of things electrical, could you please approve the work I just completed. Trust me, it's done to code and beyond.
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09-28-2011, 02:28 PM #28
Re: 12-2 with ground for multi wire
On the right side, it appears there may be 220v baseboard heaters on the first, second and fourth breakers. The other breaker on the right appears to be larger wire, with black on each terminal. On the left, the breakers are not linked, so [if] those are also baseboard heaters, they are using improper breakers. Nothing is labeled, so further investigation is required to verify what is connected. If these branches are for outlets, or any other 110v circuits, then there is a problem. Again, determine what is connected. A simple circuit tracer will do, or simply open each breaker, and see what is not powered. It's not rocket science to figure this out.
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09-28-2011, 08:55 PM #29
Re: 12-2 with ground for multi wire
Ben,
It was not my intention to rib you in my last post. I was just sharing what I thought could be possibilities. I, and I bet many others learned from this thread so thanks for starting it.
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09-28-2011, 10:33 PM #30
Re: 12-2 with ground for multi wire
Ben
No one is trying to insult your intelligence. I hope I did not make you feel that way. I do not know you or your experience level. I was simply pointing out that the picture does not prove mwbc is in use. You even mentioned that you "think" they are mulit-wires.You gave no information that would cause us to believe beyond a doubt that those circuits are multi-wires. As for wrong ... sure there are things wrong but the devil is in the details ... and you gave no details about why those circuits would have to be mwbc.
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09-29-2011, 11:23 PM #31
Re: 12-2 with ground for multi wire
Ok having any white wires under a single pole breaker is an incorrect installation and a huge safety and fire hazard.
2 conductor nmsc can only have the white wire landed under a 2 pole single phase 240V non nuetral circuit or no 120v control such as for electric water heaters or baseboard heating with 240V temp controls, well pumps, regardless they require to be installed under a 2 pole breaker.
calling in an electrician would be a good move.
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10-02-2011, 08:06 PM #32
Re: 12-2 with ground for multi wire
Ok having any white wires under a single pole breaker is an incorrect installation and a huge safety and fire hazard.
2 conductor nmsc can only have the white wire landed under a 2 pole single phase 240V non nuetral circuit or no 120v control such as for electric water heaters or baseboard heating with 240V temp controls, well pumps, regardless they require to be installed under a 2 pole breaker.
I think they are 120 volt branch circuits that have been converted to 240 volt branch circuits by the homeowner or someone else.
Should a electrician take a look and make the necessary corrections....absolutely.
Last edited by Roger Frazee; 10-02-2011 at 08:19 PM.
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10-03-2011, 05:05 PM #33
Re: 12-2 with ground for multi wire
The above gives the impression that doing what is stated is 'okay', but ... *it is not okay* to do what is stated above.
If the white wire is to be used as stated above, the white wire must be reidentified so that it is no longer 'white', it is some other approved color for an ungrounded conductor, typically either red or black, and because the other conductor in the NM cable is black, the white should typically be reidentified to red.
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10-04-2011, 07:51 PM #34
Re: 12-2 with ground for multi wire
non grounded conductors must be identified true this came into effect in the late 80's, but that is knowledge to those with code training, most 240v 2 conductor circuits are twisted to help identify them as a 2 pole circuit at the panel during make up by the electrician (PRE CODE CHANGE) than when 3 conductor 4 wire circuits came around a grounded conductor and a ground electrode conductor became mandintory. but back to the white wire under a single pole breaker it does become a fire hazard as the groundelectrode conductor become return path of any unbalance load of the circuit back to the panel, nuetrals will carry electrical current not just voltage. as a non insulated conductor with it will heat up sorrounding materials quicker (ambiant air) plus exposes those items to the chance of taking electricity to an alternate path.
we have 38 electrical fires in the residential region every hour on average, effecting450,000 homes/injuring/killing 5000 people every year by known or unknown region electrical fires, so yes this circuitry could very well be an electrical fire hazard.
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10-05-2011, 05:11 AM #35
Re: 12-2 with ground for multi wire
A GEC connects the panel to any of the acceptacle electrodes listed in Article 250 like a rod, plate etc. It will not carry any unbalanced load back to the panel, unless someone elses neutral current is leaking through the ground and returning on another neutral.
A GEC is not even run with the circuit conductors.
All answers based on unamended National Electrical codes.
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10-05-2011, 05:32 AM #36
Re: 12-2 with ground for multi wire
the circuit is using ground as the nuetral!!! look at the picture.
the non metalic sheathing and paper will not absorb/displace the same amount of heat as an insulated conductor.(agian I'm talking about embiant air heat to air displacement) this is based on electrical theory and resistance. resistance will cause deterioration on wiring, the nuetral is always the first to overheat on the circuit.
when dealing with aluminum wiring you will find the nuetral wire discolored/bubbled at the points of highest resistance (taps/terminations/spices) and beyond that. working in the field on service calls I have found hunreds of circuits with this problem, you base your answer on NEC codes, this installation is not to code we have covered that, I'm stating facts from electrical theory and years of experience in the field. using the ground as a nuetral exposes electrical current in junctions and at the panel. don't believe me go and touch a ground wire from a 120V circuit used as a neutral while under load.
Last edited by Norman Ellis; 10-05-2011 at 06:05 AM.
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10-05-2011, 07:26 AM #37
Re: 12-2 with ground for multi wire
if the nuetral is the second side to a 240V circuit then yes the ground wire (GEC) would not be used to close path of the circuit.
Ground (GEC) has been ran with circuitry since the early 60's all termination points, devices or equipment must be grounded to the GEC (minus exceptions under article 250 double insulated tooling, DC, marine, isolated special means. ECT.) or have a path to ground by mechanical ground/conduit, building ground or ground electrode under NEC code requirements. by the 70's ground conducter was required to be of same size as the circuit conductor, in the 80's the means to ground became primary in installation (set screw connectors, grounded bushings ECT...) don't try to tell me the GEC doesn't run with the path of circuit, it is in place with circuitry to give protection and provide an alternate path to ground if the service recieves an electrical surge/lightning strike or if a circuit path becomes open to prevent exposure to any conductive materials outside its normal path.
Is this installation an electrical fire hazrd????
as mentioned before 38 electrical fires an hour in the residential region, 40% from older outdated services, 20% by alterations to service by non qualified people. 20% by faulty equipment/devices or installation. other means: rodants/insects infestation, exposure to weather/bios, shifting in structure/damaged wiring and more.
I have just under 30 years in the electrical/construction/mantenace field, with over 3 years research following report from USFA (United State Fire Administration) FEMA, NFPA, ESFI (Electrical Safety Foundation International) U/L labs, Utilities commision, electrical engineering professors on causes to electrical fires, I know electricity, I know circuitry, I know NEC code.
Most people will do what it takes to make electricity work, VERY FEW will make it right, and even less will understand the danger of electricity when it is not provided a properly protected path.
The electrical enviroment developed in an occupied home is only as safe as the electrical service that provides that power.
You can be as book smart as the people that write the books or teach, but you can only be as smart in the field as the time and experience you retain.
I have never met an engineer or inspector with less than 10 years in the field that I haven't had to correct on a design/installation, and that is why I became a home inspector/consultant
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10-05-2011, 09:16 AM #38
Re: 12-2 with ground for multi wire
You might want to review the NEC Article 100 definitions.
Grounding Electrode. A conducting object through which
a direct connection to earth is established.
Grounding Electrode Conductor. A conductor used to
connect the system grounded conductor or the equipment to
a grounding electrode or to a point on the grounding electrode
system.
You are referring to an EGC, not a GEC.
Grounding Conductor, Equipment (EGC). The conductive
path(s) installed to connect normally non–current-carrying
metal parts of equipment together and to the system grounded
conductor or to the grounding electrode conductor, or both.
I have just under 30 years in the electrical/construction/mantenace field, with over 3 years research following report from USFA (United State Fire Administration) FEMA, NFPA, ESFI (Electrical Safety Foundation International) U/L labs, Utilities commision, electrical engineering professors on causes to electrical fires, I know electricity, I know circuitry, I know NEC code.
I have never met an engineer or inspector with less than 10 years in the field that I haven't had to correct on a design/installation, and that is why I became a home inspector/consultant
Last edited by Jim Port; 10-05-2011 at 11:48 AM.
All answers based on unamended National Electrical codes.
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10-05-2011, 03:56 PM #39
Re: 12-2 with ground for multi wire
I've not seen that, maybe that was a practice in your area?
I'd be concerned that the twisted wires, under high current conditions (such as approaching overcurrent conditions) the twisted wires could become a choke coil and reduce the current being allowed through to the overcurrent device.
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10-05-2011, 04:26 PM #40
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10-05-2011, 05:21 PM #41
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10-05-2011, 05:28 PM #42
Re: 12-2 with ground for multi wire
thats like saying anyone can build a car, ok you built a car, how safe is it? how long will it last under constant use?, come on be real nobody can build a car road worthy the for any amount of time the fisrt attempt,or even the second. and no one could properly wire a home their first try.
I'll say it again a non insulated conductor (ground) can not be a safe source to close path on a circuit.
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10-05-2011, 05:33 PM #43
Re: 12-2 with ground for multi wire
Jim,
I am beginning to think he may be so clueless that he did not even understand what you were pointing out ... that, to him, what he posted and you quoted still sounds correct.
Jim, Bill, you didn't know that the GEC (grounding electrode conductor) is supposed to be run with the circuit conductors? What is wrong with you two ... and me ... I didn't know that either ...
GEC (grounding electrode conductor)
EGC (equipment grounding conductor
CEG (circuit envelope grounding ... okay, I made that one up )
... What's the diff? They all have "grounding" in there someplace, don't they?
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10-05-2011, 05:36 PM #44
Re: 12-2 with ground for multi wire
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10-05-2011, 05:54 PM #45
Re: 12-2 with ground for multi wire
Current(ampers) runs on EMF (electro magnetic force)produced by your voltage. when you have wires twisted the field is reduced in size, hurtz has less fluxuation reducing resistance from travel of the electrode atom.
if you go to any hardware or electrical supply house all multi conductor cables are twisted.
have you ever seen what happens when you run parrellal feeds with one phase in each conduit next to eachother? The conduits will overheat from the EMF fields becoming unbalanced, they will colide in travel producing so much friction and heat the conductors will melt and the conduits will glow red. you need the EMF to be balanced and the best way to provide that is with a twisting pattern
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10-05-2011, 06:57 PM #46
Re: 12-2 with ground for multi wire
You really have no idea what is going on or what you are saying, do you?
Or, if you do, you have no idea what terms to use, how they are spelled, what they mean, and which terms should be used where, do you?
"ampers"
- You mean 'amperes'.
"EMF (electro magnetic force)"
- Typically, emf stands for 'electromotive force'.
"hurtz" - Hertz
"if you go to any hardware or electrical supply house all multi conductor cables are twisted."
- Not in the manner in which described. Go buy any (virtually any) grounded type round extension cord and the conductors have a gradual twist (more of a gradual spiral wrap), you described taking a short section of wires and twisting them together, which would indicate many turns in a short distance, i.e., you just made a "coil" in that sense, and when the current, frequency, and number of turns matches to the extent necessary (I have not worked with those aspects for over 40 years, so I will not even attempt to do the calculations). You will notice, though, that 'flat' two conductor NM cable also has a slight spiral affect of the conductors within the outer sheath.
"have you ever seen what happens when you run parrellal feeds with one phase in each conduit next to eachother? The conduits will overheat from the EMF fields becoming unbalanced, they will colide in travel producing so much friction and heat the conductors will melt and the conduits will glow red. you need the EMF to be balanced and the best way to provide that is with a twisting pattern"
- You are referring to eddy currents, which are the stray magnetic currents induced in the metal conduit due to the conductors being in separate conduits and their magnetic fields not canceling each other out. Those eddy currents are why, when parallel conductors are run, a complete set is run in each conduit and enter the metal enclosure in their respective conduits. There is a condition when this is not necessary, such as when the conduits are nonmetallic and they enter a nonmetallic enclosure, and they come up from the ground (I don't recall all the specifics, but there is an allowance for this condition which does not require the full set of parallel conductors to be in each conduit, etc.).
You said "I know electricity, I know circuitry, I know NEC code", but you have yet to show us that knowledge. You may have it, but you have not, and are not, displaying any of it here.
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10-05-2011, 07:51 PM #47
Re: 12-2 with ground for multi wire
Ok Jerry
shielded twisted pair RED/Black in a 110V relay circuit, Normally open what color is common? do you use the ground?
on a three phase (Y) transfomer what point do you pick up the XO (neutral) and on what side is the XO bonded? what caused a floating nuetral ?
on a three phase delta transformer what phase should be used to produce a stinger leg?
how do you change rotation on a sigle phase electric motor?
what's the wiring number pattern on a 9 wire multi voltage motor for 277V
what is the required number of entries and locations to an electrical room
with a service greater than 600AMPS?
what size ground is required on a 600 amp service?
can you install an electrical panel in a bedroom/kithen/bathroom/closet/crawl space?
what is the minimum clearance required in front of a panel?
what is the max number of slimline/space saver twin pole breakers in a 100 amp 16 opening panel?
how often should you check an aluminum circuit for loose connection/derterioration?
here is a simple one what is the max voltampers allowed on a 20 amp circuit? what is the voltamper rating on a 20 amp recepticle in a parralel 10 opening circuit?
what is the minimum size conduit entry that requires a bushing?
what size pull box by cubic inch is required for a 3 conductor 300 mcm pull box?
are you required to ground a fiber box if it contains a junction?
what is the mili amp indifference from hot to neutral to cause a GFI recept to trip?
what is the minimum depth for rigid conduit on an underground run?
What schedule PVC is required for underground runs?
can you use PVC in an elevator shaft?
can flex tubing be used on exterior runs?
what is the max length on 120v run before voltage drop is figured?
what is the minimal ohms required on a ground electrode before alternate means will be required?
all these are in the NEC code book but yet if you want a job done right or done safe than you ask will these factors effect the finished product? wil it provide a safe power source to my client. will my client alter this service during occupency of the building?
miss spelling an electrical term doesn't mean squat but maybe i did better with science and math as a kid.
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10-05-2011, 08:15 PM #48
Re: 12-2 with ground for multi wire
"Hurtz" is what the loan shark's collector puts on you when you don't pony up the vig!.
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10-05-2011, 08:45 PM #49
Re: 12-2 with ground for multi wire
Maybe you ought to just quit while you're ahead. There are multiple answers to several of your questions. The situations they are applied in determines a lot more about what you know than the fact you know how to find one answer, as does the fact you know more than one answer exists in some cases.
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10-05-2011, 08:52 PM #50
Re: 12-2 with ground for multi wire
I would say it is bold to brag about all the experience and knowledge one has when simple terminology seems to confuse them. If you can't understand the basics I don't hold much hope for the complex items. You are putting yourself out as a subject matter expert yet haven't seemed to be able to back it up.
miss spelling an electrical term doesn't mean squat but maybe i did better with science and math as a kid.
Many of your questions are so poorly worded even a knowledgeable person could not answer them.
Here are a random sampling:
what is the minimum size conduit entry that requires a bushing? Bushing or lack thereof is not based on conduit size, but conductor size.
what size pull box by cubic inch is required for a 3 conductor 300 mcm pull box? Is this a straight pull or a 90 pull? What size conduit is used?
what is the minimum depth for rigid conduit on an underground run? Anywhere from 0 to 24", depends on the location
what is the max number of slimline/space saver twin pole breakers in a 100 amp 16 opening panel? Somewhere between 0 and 8
here is a simple one what is the max voltampers allowed on a 20 amp circuit? Cord and plug connected or hardwired? Dedicated or not? Continuous or not?
Last edited by Jim Port; 10-06-2011 at 07:51 AM. Reason: added additional question
All answers based on unamended National Electrical codes.
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10-05-2011, 09:08 PM #51
Re: 12-2 with ground for multi wire
that was my point from the beginning! the panel wiring has potential to be a fire hazard! working with potential kenetic energy when not properly cconfined to its designated path you have potential of exposure to conductive/combustible materials that can produce unsafe conditions or cause a fire. is that basic and simple enough?
when you have variables in a service it increases the odds to producing a problem, types of materials used, installation requirements, quality of installation reduce these variables and provide a safer power source for your client.
The XO is landed from the secondary side on which it is produced!
the neutral is produced from the end of (Y) transformer coils
a floating neutral has POTENTIAL to inact as a hot if not bonded(bonding eliminated a floating neutral)
you can not ground a fiber box
3-5-7 tie together, 4-6-8 tie together 1 is neutral 9 is hot for a 277V motor circuit
180 voltampers is the count on a recept on a multi opening circuit of 10
any service over 600 amps requires 2 entries at opisite ends of the gear
the black wire is common on a twisted pair cable, ground is normally not applied
you can use flex tubing on an exterior run as long as it contains a drip loop
a pull box of no less than 24"x24"X6" =3465Cu" would provide proper bend raidious and storage of 3 300 mcm conductor wire pull
no more than 6 space saver twin breakers can be installed on a 100 amp 16 opening panel (breaker amp count should not be more than 125% per phase of panel total rating)
here is a trick of the trade on a ground electrode ohms test, wet down the area the night before testing and I promise it will pass
you can not install panels in closets/bedrooms/bathrooms/kitchens/crawl spaces or within 6' of running water
.02 miliamps is the tripping level on a GFI recept
and you still can not use a bare ground as return/grounded conductor on a circuit
i argue all the time about proper installation on a 4 wire recept such as for a dryer or cooking range, if an older panel has no ground electrode conductor on the neutral bar because the nuetral carries ground out to the meter before going to ground the neutral bar is not properly bonded for that type of installation, How can the ground provide proper protection for that recept terminated at the neutral bar in a main panel?
Last edited by Norman Ellis; 10-05-2011 at 10:14 PM.
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10-05-2011, 09:21 PM #52
Re: 12-2 with ground for multi wire
All answers based on unamended National Electrical codes.
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10-05-2011, 10:31 PM #53
Re: 12-2 with ground for multi wire
Every panel on the planet has potential to be a fire hazard. I do not see anything with the panel in this thread that is going to be a fire hazard. That does not mean there are not issues that are incorrect ... however the house is not going to burn down unless someone can give me details proving otherwise.
I have absolutely no idea what your point is ... all I see is someone that has a desperate need to have approval.... In psychology it's called 'need for approval' usually a result of inferiority complexes and is very obvious to recognize in your posts with the need to toot your own horn so much.
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10-05-2011, 11:54 PM #54
Re: 12-2 with ground for multi wire
I'm not tooting my own horn, no more than jerry would be. if any thing i'm over protective to potential hazards. and the worse part about that is no one else sees this issue with how electricity is provided to their clients, what potential is for them after they move in and develop their electrical environment, creating problems, causing loss of property, and even worse loss of lives of their loved ones.
electricity has been around for over one hundred years it has become too easly obtained/accessible by the occupent. you see homes with multiple types of wire running to the service, yet most inspectors will not give it a second glance. how many homes have you inspected with aluminum wiring and passed it without checking all connections or splices for tightness?
how many homes have you passed inspection on without checking the ampload or for a balanced load at the panel?
how many homes have you passed inspection on with multiple types of breakers in a panel?
how many homes have you passed inspection on with fuse boxes converted to junction boxes with the old wiring still in use?
how many homes have you passed inspection on with a so called panel upgrade with existing circuit not being tested for deterioration level on the wiring?
how many homes have you passed inspection on with stablock devices still in use ?
how many homes have passed inspection on with a Federal pacific panel in use?
this is just a small number of caused to electrical fires in the residential region.
deterioration/faulty devices/overloaded circuits is main cause to fires in homes over 40 years old. but hey you made your money, who cares the home owner probebly caused the fire.
well the electrical environment is only as safe as the electrcal service that provides that power. potential kenetic energy senses no difference in the path it takes, no conductor/equipment is immune to deterioration and the worse part about that90% of it is hidden from view so out of sight out of mind. it work its fine.
NEC code only helps reduce these factors, but yet when codes change, materials are found defective the home owner is left with these items in their home's electrical service. and most of these changes are not found BECAUSE???? they are hidden from view at time of an inspection on an older home.
so am I tooting my own horn??? I don't think so, my reasoning is to open others eyes to potential problems normally missed or passed over as minimal.
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10-06-2011, 05:16 AM #55
Re: 12-2 with ground for multi wire
Wrong, not all panels are listed for use with tandems.
You make posts where you say how safety conscious you are and how cautious people need to be around electric, but here you are telling people how to attempt to circumvent the rules? WTH? There are probably many soil types where even wetting the soil would not get you below 25 ohms. Given the cost of both the testing equipment and the time to test and show the inspector it is easier and more cost effective to drive a second rod and be done with it.
Show us the code prohibitions against panels in kitchens, bedrooms or within 6' of running water.
Electrical panels are commonly installed in closets especially in commercial work. The prohibition is they cannot be near easily ignited materials and the workspace requirements are needed.
Wrong again, the Class A GFI trip level is 4-6 mA.
The return current is not going to ground. It is going to its' source, ie the transformer. The range circuit would not have a ground electrode conductor. Grounding electrode conductors go from the panel to an electrode like a rod or plate as was pointed out above. You are confusing GEC's with EGC's. Same letters, different order, but a world of difference in function. To borrow someone elses words, differences with a distinction.
Last edited by Jim Port; 10-06-2011 at 09:42 AM.
All answers based on unamended National Electrical codes.
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10-06-2011, 05:49 AM #56
Re: 12-2 with ground for multi wire
All answers based on unamended National Electrical codes.
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10-06-2011, 06:53 AM #57
Re: 12-2 with ground for multi wire
Like I said you are in desperate need to seek approval and again what the heck is your point with all the FAQ ? FWIW you would have a difficult time passing license testing for an electrician yet alone a home inspector with all the inacurracies in your answers but again some of this is due to your misunderstanding of terms and how electricity returns in a residential 3 wire system. For example you would never say terminate your neutral connection to the end of the Y coils as the neutral does not connect to the 'end' of anything. If it did you would have a phase conductor at line voltage. However I think I know what you mean and it may look that way in a configuration picture but it is really called the 'midpoint' or 'neutral point' of the system.
What really is confusing me with your explanations is the continued referral to the return of current to earth via the grounding electrode conductor ..ie..you said something like the neutral carries the ground to the meter before it goes to earth (ground) ? I'm not following ???
I think what I should do is ask you to explain why a circuit breaker will trip when a fault to ground occurs in a residential system of 3 wire 120/240 service. Explain the flow of fault current and that should clear things up for us.
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10-06-2011, 09:35 AM #58
Re: 12-2 with ground for multi wire
I would hardly say all. I would call a xx-2 NM a multi-conductor cable and it is flat with no twisting of the conductors under the sheath. Even most xx-3 seems to be just the 4 conductors under the sheath without a defined twist pattern. Type UF cable is also flat, including the xx-3 variety. SER cable has the conductors laying parallel, although there can be a slight twist under the sheath. Type MC and Type AC cables don't exhibit any more twisting than xx-3 Type NM.
In fact, the one wiring method that has what I would call a defined twisting is CAT5 phone wire.
All answers based on unamended National Electrical codes.
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10-06-2011, 09:50 AM #59
Re: 12-2 with ground for multi wire
Twisting pairs is not done f\or power cables.
Twisted pair is used for audio and low voltage control cables. The twist is used to defeat noise.
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10-06-2011, 02:00 PM #60
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10-06-2011, 02:05 PM #61
Re: 12-2 with ground for multi wire
yes the twist is required to be carried to no more than 1/2" from terminations (the less straight area the better) on cat 5 or newer. but the twist reduces hertz differance through travel, addressable devices require a clean defined hertz level for control demands from the control module.
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10-06-2011, 02:54 PM #62
Re: 12-2 with ground for multi wire
Originally Posted by Jim Port
Have you looked at a piece of SE cable with its bare neutral? What about the bare neutral in a piece of aerial triplex? Does this conductor complete the path back to the transformer?
All answers based on unamended National Electrical codes.
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10-07-2011, 05:52 AM #63
Re: 12-2 with ground for multi wire
Fault
surge/disruption/dead short in a circuit SHOULD cause a fuse to blow or a breaker to trip.
Surge
A sudden/abrupt increase of voltage/currant
disruption
voltage drop/detected break to normal path/flow of electricity
Dead Short
a/c or d/c source takes direct contact to ground
OK the older service has the ground electrode landed at the meter neutral bar making the neutral carry ground electrode path from the main panel to earths ground, so even if the dryer recepticle is wired as a four wire it only provides 3 (ground and neutral are parallel not grounded conductor plus ground protection) most all electrical background people will disagree that the neutral will carry ground, but think back at the transformer were the neutral is created the purpose of ground is to prevent a floating neutral (on a/c power source) or the neutral can become a power source. thus it is a grounded conductor to complete/close path of a circuit, it is not ground nor should it be used as ground to protect against surge/fault to the earth ground electrode.
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10-07-2011, 04:43 PM #64
Re: 12-2 with ground for multi wire
Incorrect.
The fault could be a minor fault, like what trips a GFCI protective device, and there is no way that it will blow a fuse or trip a breaker.
Surge
A sudden/abrupt increase of voltage/currant
disruption
voltage drop/detected break to normal path/flow of electricity
Dead Short
a/c or d/c source takes direct contact to ground
A "short" is a direct/indirect contact between hot and neutral or two hot conductors, i.e., the "circuit" is "shorted" out - which simply means that the circuit is shortened to being from the supply to the "short", and a full and direct "short" will then effectively 'shorten' the circuit such that anything beyond the "short" is effectively no longer in the circuit.
Let's say that you have a string of 20 lamps and there is a "short" between the hot and neutral after the 3rd lamp, the circuit no longer contains the other 17 lamps, the circuit has been shorted to only the first 3 lamps (the circuit has been 'shortened', if you will, that the circuit now only contains the lamps between the supply and the "short").
OK the older service has the ground electrode landed at the meter neutral bar making the neutral carry ground electrode path from the main panel to earths ground, so even if the dryer recepticle is wired as a four wire it only provides 3 (ground and neutral are parallel not grounded conductor plus ground protection) most all electrical background people will disagree that the neutral will carry ground, but think back at the transformer were the neutral is created the purpose of ground is to prevent a floating neutral (on a/c power source) or the neutral can become a power source. thus it is a grounded conductor to complete/close path of a circuit, it is not ground nor should it be used as ground to protect against surge/fault to the earth ground electrode.
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10-07-2011, 05:13 PM #65
Re: 12-2 with ground for multi wire
Is this really what I am seeing? You are correct this is a mess.
Apollo Home Inspection
St. George UT
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