Thread: maximum amps in a panel

Hi all, need some help checking my thinking, I can't find my formulas. 1965 house with basement sub-panel, breakers total 180 amps ( 4 - 15 amp/120 volt + 2 - 50 amp / 240 volt + 1 - 20 amp /240 volt = 180 amps) 180 amps x 75% = 135 amps, panel is rated for 125 amps max. Did I do math correct to say panel is overloaded? yes the neutral and ground are not separated and isolated and yes one breaker is double tapped and strain releif is missing, etc. etc.. The main panel upstairs is a 100 amp max panel. that is a problem in itself feeding the 125 amp max panel.

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Steve,

I would tend to disagree. If you turn on every appliance and light in the house, then it might trip the 100 amp main. But, that is what the main is for. It is not really a safety issue as long as the breakers are functioning and the wires are sized correctly. Unless a lot of high amperage appliances are being used simultaneously, the number of circuits does not really have an effect on the panel amperage.

The 125 amp panel protected on a 100 amp circuit breaker should be fine as well. The panel cannot be feed by more than 125 amps, but less is OK.

Originally Posted by Steve Miskinis

Hi all, need some help checking my thinking, I can't find my formulas. 1965 house with basement sub-panel, breakers total 180 amps ( 4 - 15 amp/120 volt + 2 - 50 amp / 240 volt + 1 - 20 amp /240 volt = 180 amps) 180 amps x 75% = 135 amps, panel is rated for 125 amps max. Did I do math correct to say panel is overloaded? yes the neutral and ground are not separated and isolated and yes one breaker is double tapped and strain releif is missing, etc. etc.. The main panel upstairs is a 100 amp max panel. that is a problem in itself feeding the 125 amp max panel.

By the way,

What is that thing off to the right of the panel?

Originally Posted by Steve Miskinis

Hi all, need some help checking my thinking, I can't find my formulas. 1965 house with basement sub-panel, breakers total 180 amps ( 4 - 15 amp/120 volt + 2 - 50 amp / 240 volt + 1 - 20 amp /240 volt = 180 amps) 180 amps x 75% = 135 amps, panel is rated for 125 amps max. Did I do math correct to say panel is overloaded? yes the neutral and ground are not separated and isolated and yes one breaker is double tapped and strain releif is missing, etc. etc.. The main panel upstairs is a 100 amp max panel. that is a problem in itself feeding the 125 amp max panel.

Steve,

First, I don't see any subs around there, all I see is a panel ...

Your math is a great exercise but of no use, unless you like doing math (sometimes I do, sometimes I don't).

Why is it a problem feeding a 125 amp panel from a 100 amp panel?

To answer your question regarding the proper protection for the 125 amp panel I have to ask a question: what size breaker was it fed from in the 100 amp panel, and, what size breaker was protecting the 100 amp panel?

If there was a 100 amp main protecting the 100 amp panel, then you could have a 200 amp breaker feeding the 125 amp panel in the basement as the 100 amp main *IS* protecting BOTH panels ... the most you will get out of BOTH panels combined is 100 amps.

Also not that that panel in the photo is a Zinsco panel, so there is no danger of the breakers falling out with the dead front cover removed, there is also the very likely possibility that those breakers have welded themselves to those bus bars - that is not a good thing, and is one reason why Zinsco panels should be called out for being replaced.

The thing off the right side is something the local power company used in the past, not really sure why, have been told by local electrician and power company people that there is no risks if still in place and most electricians remove when servicing panels.

Originally Posted by Gunnar Alquist

By the way,

What is that thing off to the right of the panel?

Looks like a one-time surge protector.

May or may not be any good, but its installation is not good, and not just the fact that it is not mounted properly either.

Originally Posted by Steve Miskinis

The thing off the right side is something the local power company used in the past, not really sure why, have been told by local electrician and power company people that there is no risks if still in place and most electricians remove when servicing panels.

Steve,

I was just curious because it looks like it is double-tapped off of the line terminal.

yes it is double tapped.

Jerry,

from what I could visualize in the main panel and in the pictured sub-panel, this panel is feed directly from the meter, there was no breaker in the main labeled for the sub and no wiring that appeard to be to the sub. so actually it is not a sub-panel if it is direct from the meter.

Originally Posted by Steve Miskinis

Jerry,

from what I could visualize in the main panel and in the pictured sub-panel, this panel is feed directly from the meter, there was no breaker in the main labeled for the sub and no wiring that appeard to be to the sub. so actually it is not a sub-panel if it is direct from the meter.

Steve,

I hate to say this so bluntly, which is why I hinted at it in my first post, but YOU ARE NOT ... I repeat *NOT* ... you are NOT looking at a "sub-panel".

There is no submarine there.

You are looking at *A PANEL* (more precisely a "panelboard", but suffice it to say "panel").

Your description above states that you may be looking at SERVICE EQUIPMENT in the photo.

It would help you to use correct terminology, and help us to help you by you using correct terminology. There was a recent thread which had this SAME VERY COMMON PROBLEM ... the problem of not properly identifying what you are looking at by using the wrong terms to describe what you are looking at.

Let's start all over.

In your first post you state the panel in the photo is supplied from the other panel, in the post quoted above you state it goes back to the meter??? I am thoroughly confused.

There is a meter OUTSIDE.

Where is the SERVICE EQUIPMENT with the main service disconnect?

From the "service equipment" what feeds the other panel?

From the "service equipment" what feeds the panel in the photo?

Remember, there are not "sub" panels in "houses" only in "submarines", so you either have "service equipment" or "non-service equipment" and you could have a "panel" at either "service equipment" or "non-service equipment" locations.

So leave out the "sub" references and just describe what "panel" is fed from where and where the main disconnect is.

We can help you sort it out from there.

Steve,

We need a better description and more information as to what feeds what before we can be of help.

Adding the values of the breakers installed in a panel is of no use in determining the load on the service. A 40 ckt panel filled with 20 amp breakers does not mean that there is an 800 amp load installed.

The correct usage is subpanel. NO hyphen.
Incorrect ------> sub - panel
correct - ------->subpanel

"Sub" is a prefix and has nothing to do with the navy's fleet of under water vessels.

sub - , 1. a prefix occurring originally in loan words from Latin the stems of which are
sometimes not used as words(subject;subtract;subvert);on this model,attached freely
to elements of any origin and used with the meaning "under" "below" "beneath"
"slightly" "imperfectly" "nearly" "subordinate" " secondary".

The term subpanel is referring to a panel that is fed from another panel. Thus the second panel (or subpanel) is a secondary panel of the first panel.

Originally Posted by ken horak

The correct usage is subpanel. NO hyphen.
Incorrect ------> sub - panel
correct - ------->subpanel

The correct usage is submarine panel, there is NO hyphen and IT IS two words.

It may please some folks to try to limit the language to their own preferences - but such an exercise is like peeing in your pants. It may make you feel warm all over, but really puts everyone else off!

We have subwoofers, substations, and even subsidiaries and subordinates. There's no reason we can't call a panel that is subsidiary to the main panel a subsidiary panel - or subpanel for brevity.

Not mentioned in the NEC? So? Neither are substations or cat-5 wiring ... yet somehow we all know what's being discussed.

It's no accident that even the Oxford dictionary is revised annually, to update it to reflect contemporary useage. It ain't no accident that humongous book has an entry for 'subpanel.'

You would need to find out what the load for each breaker is to come up with the load calculation for the panel. I would be more concerned that the breaker that protects this panel and feeder wire is sized correctly.

Where are the box connectors? Only see them on the feeder.

...wow. My first reactions to photo...

Rust a big clue that water sat in that basement. There is also a double tap third down on right...and check out unsealed opening bottom of panel...

On and on.

Big ol lightning arrestor?

[...breakers total 180 amps ( 4 - 15 amp/120 volt + 2 - 50 amp / 240 volt + 1 - 20 amp /240 volt = 180 amps) 180 amps x 75% = 135 amps, panel is rated for 125 amps max. Did I do math correct to say panel is overloaded?]

Where did you get the impression that we calculate loads for electric systems? And where did you get 75%? In the first place this is way out of our scope, we really don't have any training for this and IF you were to venture there, the NEC has a long detailed process for an electrician to calculate loads based on the number of electric fixtures/receptacles/etc. and the time 'the maximum' load will be applied to the panel NOT the total breaker ratings. They have nothing to do with it. I've seen 200 amp panels with 700 amps of breakers in it and it was fine. I did call it out for further analysis and the electrician measured amperage draw with inductive meters...it didn't draw more than 140 amps.

I think everyone else has addressed the other issues. I just wanted to mention about this math issue. Thanks for posting...the 'sub' thing is really a controversial sore.

Also looks like wires enter the panel without bushings.

Steve you are perfectly welcome to use the word or words SUB-PANEL or SUBPANEL on this board and everyone here will know what your talking about. Just don't expect Jerry to respond without a 5 minute lecture on the subject. Some people like proper names instead of slang's or nick names like watch out for that pile of K-9 fleece instead of LOOK OUT for that dog &#!*! to each his own

Originally Posted by Tony Mount

Steve you are perfectly welcome to use the word or words SUB-PANEL or SUBPANEL on this board and everyone here will know what your talking about. Just don't expect Jerry to respond without a 5 minute lecture on the subject. Some people like proper names instead of slang's or nick names like watch out for that pile of K-9 fleece instead of LOOK OUT for that dog &#!*! to each his own

Tony, Steve,

The reason for using the correct words was made ever so evident (except that Tony missed them, because he refuses to learn the differences needed to understand the reason for the correct terms) in your post, Steve.

That IS NOT, by your description, anything other than "service equipment", and to call that, or accept calling that (as Tony is doing) a "subpanel" or "sub-panel" is not only doing a disservice to your client (who probably does not know the difference) but a disservice to yourself (who SHOULD know the difference), AND TO THIS PROFESSION by so blatantly misusing terminology.

There are reasons for using the correct terminology, and even as John himself refuses to use the correct terminology, he has therefore made mistakes based on assuming that what he was talking about was what was being talked about.

Here is what I am talking about:

Originally Posted by Steve Miskinis

1965 house with basement sub-panel

Originally Posted by Steve Miskinis

from what I could visualize in the main panel and in the pictured sub-panel, this panel is feed directly from the meter, there was no breaker in the main labeled for the sub and no wiring that appeard to be to the sub. so actually it is not a sub-panel if it is direct from the meter.

That panel is "service equipment", however, because of being predisposed to use the term "sub-panel" he referred to that as a "sub-panel" and continued to do so, even when ending up saying "so actually it is not a sub-panel if it is direct from the meter".

The advantage to home inspectors of dropping the "sub-panel" and "subpanel" term is that they would then immediately be able to recognize when something is "service equipment" and "not service equipment", with a "panel" being a part of either, or both.

I have absolutely NO expectation that you, Tony, will ever learn anything or even try to improve your grasp on inspections and reports, however, I do hold out hope that others are not of like thinking.

Jerry is quite correct in his "service equip & non service equip" terminology but as an electrician for many years in my past life, I can honestly say that almost everyone refers to the non-service equip panels as subpanels. In fact, not doing so creates confusion when discussing these sorts of issues with most clients.

It would be very important to use the correct terminology when discussing things like Bonding, Grounding or Neutrals etc.... On second thought, maybe important if you're in court defending one's position but even tradespeople or an electrician would understand what was being discussed if the term subpanel was used.

Not a big deal, but I'm sure Jerry will have a different opinion

Originally Posted by Joe Klampfer

I can honestly say that almost everyone refers to the non-service equip panels as subpanels.

I must presume, then, that you have never seen an electrical installation in which there is the service equipment with a main disconnect which feeds THE panel? THE ONLY panel? And you are calling that a "subpanel"?

No wonder there is so much confusion where you are.

In fact, not doing so creates confusion when discussing these sorts of issues with most clients.

You mean without you first explaining what it what.

Virtually every client I have ever talked with understands "electrical panel" as being where the breakers/fuses are, and those are certainly not "subpanels", they are "electrical panels".

You must be dealing with a lot of clients who are misinformed electrician wannabes who learned their jargon down at the Big Box store, where "everything is a subpanel" and where "as long as you connect white to white and black to black" you will be okay.

It would be very important to use the correct terminology when discussing things like Bonding, Grounding or Neutrals etc....

Precisely correct and why I keep pointing that out.

Jerry, Do you not see how much information you have to use just to say the electric service consists of a main disconnect and a sub panel and yes it is a sub panel because the ground and naturals must be together in the first disconnecting means from the meter. Now is there any one on this board that does NOT know what I 'am talking about? There is not a lay person on the street that would have any Idea what a non-sevice equipment is so why use it. Aint aint a word either and we still us it because it just easyer.

Originally Posted by Jerry Peck

I must presume, then, that you have never seen an electrical installation in which there is the service equipment with a main disconnect which feeds THE panel? THE ONLY panel? And you are calling that a "subpanel"?

No wonder there is so much confusion where you are.



You mean without you first explaining what it what.

Virtually every client I have ever talked with understands "electrical panel" as being where the breakers/fuses are, and those are certainly not "subpanels", they are "electrical panels".

You must be dealing with a lot of clients who are misinformed electrician wannabes who learned their jargon down at the Big Box store, where "everything is a subpanel" and where "as long as you connect white to white and black to black" you will be okay.



Precisely correct and why I keep pointing that out.

First off Jerry, I fully understand what you're saying so there is no confusion "up here". In your first description, I would call that the main service disconnect (which feeds the main panel). The term 'main panel' is only used to indicate that it is the main panel - ahead of the others, which would be fed from the main panel (seesh man, I can't believe this needs soooo much discussion to clarify!). Now, lets carry on with this elementary story... Any panel(s) which are now fed off the MAIN panel would be now called subpanel A, subpanel B... etc Simple concept.

In the event of a main service disconnect feeding into a splitter cabinet with multiple conduit feeds coming off to supply other disconnects or panels would not be called subpanels but rather Panel A, Panel B ... etc

There's no need to further beat this to death or sling cheap insults at each other over who wants to be a wanna be electrician or anything else because I could give a rat's ass what you call it, all I'm saying is that everyone, whether they are electricians or regular handymen will understand the condition being discussed and I have NEVER seen confusion on this topic until I read your attempts to ensure everyone follows the "correct terminology"

Jerry-
If what you are describing is a main panel with a main breaker then that is the main service. If it is a main service disconnecting means (disconnect either fused or enclosed circuit breaker) that in turn feeds a panel, then yes the panel is a subpanel. The main disconnecting means is the service.

Originally Posted by Tony Mount

Jerry, Do you not see how much information you have to use just to say the electric service consists of a main disconnect and a sub panel

Ah ... Tony ... no where have I said it consists of an main disconnect and a "sub panel".

I don't know which comic books you are hiding in that outer book, but it would be in your best interests to put that comic book down and set it aside.

and yes it is a sub panel because the ground and naturals must be together in the first disconnecting means from the meter.

Tony, what have you been smoking? Maybe you'd like to share it with the rest of us so we can understand where you are coming from?

Originally Posted by Tony Mount

Do you not see how much information you have to use just to say the electric service consists of a main disconnect and a sub panel and yes it is a sub panel because the ground and naturals must be together in the first disconnecting means from the meter.

Originally Posted by Joe Klampfer

In your first description, I would call that the main service disconnect (which feeds the main panel). The term 'main panel' is only used to indicate that it is the main panel - ahead of the others, which would be fed from the main panel (seesh man, I can't believe this needs soooo much discussion to clarify!).

Joe, Tony,

You two need to converse and get your stories straight so they match.

Originally Posted by ken horak

If what you are describing is a main panel with a main breaker then that is the main service.

Actually, it is "the service equipment", which includes the service disconnect/main disconnect, and may, or may not, include a panel within it.

If it is a main service disconnecting means (disconnect either fused or enclosed circuit breaker) that in turn feeds a panel, then yes the panel is a subpanel.

No, that panel is a ... (drum roll) ... what you just said: a "panel".

The main disconnecting means is the service.

No, the main disconnecting means is "part of" the "service equipment".

You keep using the term "the service" when that includes everything from the transformer to the service equipment.

In there you have the overhead "service" drop or underground "service" lateral, then you have the "service" mast riser or the underground "service" riser, then you have the meter, then you have the "service" entrance conductors, followed by the "service" equipment which includes the "service" disconnect/main disconnect, finally you have the "service" overcurrent protection (which is typically one and the same with the "service" disconnect/main disconnect.

After you leave the load side of the "service equipment" and you go to a panel, that is called a "panel", or a "distribution panel", or a "loadcenter panel", or a "panelboard", and you may have a "panel" located at and part of the "service equipment" which makes that the "service panel" and the next panel down becomes "a panel" (or one of the other names you prefer to call it above), and, to help designate *WHERE* a second "panel" may be in relation to the first "panel" one might even refer to it as a "remote panel".

ALL "not service equipment" "panels" are wired the same - the neutral is isolated from ground - not because it is a "panel" but because it is "not service equipment".

ALL "service equipment" ("panels" or no "panels" as part of them) are wired the same - the neutral is bonded to ground at the "service equipment" - not because it does or does not have a "panel" but because it is "service equipment".

If this service equipment panel comes from the meter also, then it is double-tapped at the meter? Thats acceptable or am I missing the boat somewhere? Thanks

Originally Posted by Brian Robertson

If this service equipment panel comes from the meter also, then it is double-tapped at the meter? Thats acceptable or am I missing the boat somewhere? Thanks

Brian,

The problem is, with his description, we really do not know what came from where or what fed what. So we are ALL missing the boat here (Steve took the boat when he left) ... so until Steve comes back and properly describes what was fed from where ... we have missed the boat.