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  1. #1
    Roger Kautz's Avatar
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    Default Rating of split buss panel.

    The panel is a CH - apparently a split buss, and the question the Realtors and lenders want answered is "whether the house has 100 amp or not". The house was from 1956, but the wiring in the panel looks much newer. Stacked at the top are 3 breakers; a 30 amp, 40 amp, and 50 amp. At the top of the 30 is the top of a buss, where the service cables are attached. But from the same terminals, other cables run off the buss before the breaker, and they run down the side of the panel and connect to the 50 amp. It appears the top buss feeds the 30 and maybe 40 amp breakers. The other set of wires feeds the 50, which apprently in turn feeds all the 15 and 20 amp breakers on the lower buss. The service coming into the panel seems to be #4 copper. I asked an electrician, who said based on my description and what he has seen, he would say there appears to be 100 amp service coming into the house, but there is no point on either buss at which 100 amps is available, so the panel is not 100 amp. (For reasons I am not sure of, I do not remember what the meter looked like.) This is not the "yes or no" answer the lender wants. What is the correct and practical answer to give them?

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  2. #2
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    Default Re: Rating of split buss panel.

    IMO...the service size is determined by the amperage rating of the SEC or the panel rating....whichever is smaller.


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    Default Re: Rating of split buss panel.

    Quote Originally Posted by Roger Kautz View Post
    ......, he would say there appears to be 100 amp service coming into the house, but there is no point on either buss at which 100 amps is available, so the panel is not 100 amp.
    This logic is flawed. The fact that 100A cannot be draw from one location does not matter. There is the top "utility" half with several (up to five) appliance breakers, and the lower section, fed from another breaker commonly referred to as the "lighting main". This allows the maximum number of six "main" breakers.

    That is a 100A panel. If everything else in the service is rated for 100A (or more) then that IS a 100A service.


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    Default Re: Rating of split buss panel.

    Roger,
    "lenders want answered is "whether the house has 100 amp or not"
    First you need to obtain exactly what the lender is asking for.
    Are they asking for the service cable size that determines the size of every thing that follows.
    Or are they asking for the panel rating.
    I would be careful as to how I would word your response. Get their question in writing and respond to exactly how they worded their question, more over I would have an Electrician provide the answer directly. That way they are not coming back on you for a possible wrong answer. It is like a test with a trick question that you have to not read more into the question to formulate the answer.

    Service drop to meter is __________.
    Meter is rated for ____________.
    Service cable into house/panel is ___________.
    Panel is rated for ______________.

    Only answer what you know not what you think.


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    Default Re: Rating of split buss panel.

    Where is the door? Is that water or ice on/in those basement block walls?

    That's an ancient split bus panel with bus rating limitations.

    See label inside, read limitations, see wiring diagram. Wire bending radius.

    I believe I see some wafers/minis at the bottom - I do not believe they belong there, the wiring diagram/bus diagram and the panel labeling will confirm (ratings, limitations and ratings), but would pre-date such. I do not recall a legitimate classified breaker that could be used without a field modification that would not be in keeping with either the original panel listing or the classified breaker(s) in that position in that panel.

    If I am correct in what I see and remember for such a vintage panel - it would indicate the panel is overloaded - thus remediation and/or replacement warranted.

    Recommendation for an electrician to confirm and/or perform load calculations is always an option. The panel itself is obsolete, safety standards have changed significantly for such equipment over the years.

    Search the forum for bus stab ratings or bus stab limitations - Roger F. has posted on this subject and done a very good job at explaining what these indications and limitations mean.

    Are you going a "regular" HI, or a VA or HUD/FHA condition/appraisal report for the loan originator?

    Last edited by H.G. Watson, Sr.; 01-28-2011 at 03:34 PM.

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    Default Re: Rating of split buss panel.

    Kind of looks more like adhesive than moisture, like something had been glued to the wall at one time.

    "It takes a big man to cry. It takes an even bigger man to laugh at that man". - Jack Handey

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    Default Re: Rating of split buss panel.

    Quote Originally Posted by H.G. Watson, Sr. View Post
    Where is the door? Is that water or ice on/in those basement block walls?

    That's an ancient split bus panel with bus rating limitations.

    See label inside, read limitations, see wiring diagram. Wire bending radius.

    I believe I see some wafers/minis at the bottom - I do not believe they belong there, the wiring diagram/bus diagram and the panel labeling will confirm (ratings, limitations and ratings), but would pre-date such. I do not recall a legitimate classified breaker that could be used without a field modification that would not be in keeping with either the original panel listing or the classified breaker(s) in that position in that panel.

    If I am correct in what I see and remember for such a vintage panel - it would indicate the panel is overloaded - thus remediation and/or replacement warranted.

    Recommendation for an electrician to confirm and/or perform load calculations is always an option. The panel itself is obsolete, safety standards have changed significantly for such equipment over the years.

    Search the forum for bus stab ratings or bus stab limitations - Roger F. has posted on this subject and done a very good job at explaining what these indications and limitations mean.

    Are you going a "regular" HI, or a VA or HUD/FHA condition/appraisal report for the loan originator?

    Cutler-Hammer XO panels never had a "mini" breaker, the 2-poles came in 2 widths, the normal ones which take the space of 3 single pole breakers & the one shown in the bottom of of picture #2 which only requires 2 spaces & is somewhat rare, even more so considering they have been obsolete for more then 50 years.


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    Default Re: Rating of split buss panel.

    Its a twin or tandem breaker provides two SP circuits in a single molded case, fits in the space for one regular size single pole 120 v breaker.

    This is a Non-CTL split bus panel as service equipment.


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    Default Re: Rating of split buss panel.

    Quote Originally Posted by H.G. Watson, Sr. View Post
    Its a twin or tandem breaker provides two SP circuits in a single molded case, fits in the space for one regular size single pole 120 v breaker.

    This is a Non-CTL split bus panel as service equipment.

    It is not a twin & the standards for CTL loadcenters did not exist for many years when the panel was built.


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    Default Re: Rating of split buss panel.

    Quote Originally Posted by H.G. Watson, Sr. View Post
    If I am correct in what I see and remember for such a vintage panel - it would indicate the panel is overloaded - thus remediation and/or replacement warranted.
    From what I see that is mostly original wiring. Can you tell me what fact you are basing this statement on?
    Sure the panel is outdated, but that does not mean it is "overloaded".

    I'm sorry, but I read ,and re-read this post, and I am more confused that ever.


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    Default Re: Rating of split buss panel.

    Petey, all those years in the electrical trade and you still can't tell a panel is overloaded based on age or looks?


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    Default Re: Rating of split buss panel.

    Limitations as to the number of circuits permitted on the sub-buss when the panel is used as service equipment, and the rating, buss and stab limitations for same.

    This information would also be on the label and wiring diagram for the equipment.

    As mentioned, this subject has been covered extensively on other topic threads - and has nothing to do with load or demand calculations, and everything to do with the design limitations of the panel. As I am recalling, no 240 loads were or are allowed off the lighting main sub-buss either.

    I know of no legitimate, listed, or classified use of a field modified CTL breaker in a non-CTL panel. I do not recall this vintage panel authorized or to use classified twin breakers or tandems on the sub-buss in service equipment application, with all other postions filled with full size breakers and keeping with the limitations of the equipment.

    Breakers manufactured beyond the 50s & 60s.

    please excuse the earlier reference to mini/wafers - I had a brain glitch, I meant twins or tandems.



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    Last edited by H.G. Watson, Sr.; 01-29-2011 at 11:14 AM. Reason: inserted magnified pic

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    Default Re: Rating of split buss panel.

    Quote Originally Posted by Jim Port View Post
    Petey, all those years in the electrical trade and you still can't tell a panel is overloaded based on age or looks?
    I'd take Petey's judgment (and Rollie's info) in the matter over HJ's any day. A good look at the panel front shows NO provision for a door - many old panels didn't have them. How do you apply CTL rules to a panel built before they existed?

    At any rate, there appears to be a very intact label in the panel that might answer a bunch of questions if anyone bothered to read it. And, I'd expect a label on the "questionable" breaker(s) would also be necessary if it had gone into production after the label on the panel left the printer.

    Absent info on the meter and meter housing and service wire size from the POS to the meter everybody is just guessing on service size anyway. The wire present in the panel that supplies the "main" buss appears to be #4 and would suggest that the service is in fact a 100 AMP.

    Jim, I can completely fill a panel with breakers and not even begin to load it to capacity, and overload it with just a single breaker installed. I'd be interested in the info you use to make the visual determination of the panel being overloaded, especially given there is no info on the number of maximum circuits permitted and what breakers types are permitted to be installed. I'd also have questions about what, if any rules were being enforced when and where the panel was installed.

    I work dilligently at a trade and have for close to 40 years. I learn AT LEAST one new thing every day about it and don't pretend to know near as much about it as some of you guys that "dabble around the edges", and only as part of your inspection activities. Are you really that good? Really? Just by LOOKING? I'm frickin' impressed.


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    Default Re: Rating of split buss panel.

    Other 'lookee-here' areas.

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    Default Re: Rating of split buss panel.

    Quote Originally Posted by H.G. Watson, Sr. View Post
    As I am recalling, no 240 loads were or are allowed off the lighting main sub-buss either.
    So, would multiwire branch circuits be out of the question? Pretty common in older houses


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    Default Re: Rating of split buss panel.

    In the 1950's there was no such thing as a "CTL assembly" there was no such thing untill about 1968 and the XO loadcenters made by Cutler-Hammer & the SQ D Co. were no longer in production. Trying to apply non-existant standards to equipment is foolish, at the time of manufacture & intstallation the standard did not exist nor did the code rule requiring a "hold down" device on a back-fed circuit breaker which is also present in that panel.......


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    Default Re: Rating of split buss panel.

    When used as service equipment only 120V breakers are allowed in that portion of this older, split buss panel, NOT 120/240 breakers.

    You can't apply your logic of today with equipment manufactured to standards, 8, 9 UL standard editions ago.

    The THIN/SLIM 2-pole 120/240 (piggyback, etc.) breaker is not allowed on the L&A submain buss'.

    The 120V (no slant rating, not to exceed 120v) breakers on the L&A submain must be mounted on busd bars with words "on" alternating in opposite positions, "To balance load" and not exceed the limitations expressed on the listed and labeled instructions.

    Replacement Sq.D XO 115s and 120s were still being mfg into the 70s, this is not a panel area for use of sq.D. 120/240 X0215 or 220 "thins".

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    Last edited by H.G. Watson, Sr.; 01-29-2011 at 08:15 PM.

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    Default Re: Rating of split buss panel.

    There is more to be considered than just the short circuit rating, temperature ratings, etc.

    Vintage of panel, apparent vintage of equipiment present, and the information supplied, via post and photos, and without confirmation of materials and information from the specific equipment, I would call this as falling short of 100 amps safety-wise, It is set-up at 70 amps @ and configuration is 60C, without verification to the contrary (and was likely "designed" at 60A); cable tap to submain buss', temp.

    Weakest link in the chain. Limited at temperature - buss, breakers, panel/cabinet, and cable/conductors for the period. Unless marked to the contrary.

    Circuit breakers and panelboards also have a temperature rating. Most modern circuit breakers will be marked 60/75 C. This means that this circuit breaker can be used with wire being operated at its 75 degree C rating without doing damage to the circuit breaker, buss, and other equipment therein.


    However (there always seems to be one of those), the entire panel must be listed for use at that temperature. Older panels will not have the higher temperature rating (neither will most very much older circuit breakers equal to or less than 100 A). In order to find out if your existing panel is rated for 75 degree ampacities, you will need to read all of those fine print labels. For us older guys, that means break out the magnifying glass. You cannot just stick a new circuit breaker into an old panel and assume that it will be safe.


    During your exploration of all the fine print, you should be looking for some indication that 75 degree wire can be used at its full temperature rating. What you're hoping to see is a reference to 60/75C for conductor to the sub main, terminals, breakers and buss'. If you don't see the 75 degree listing/labeling (and on the breakers), then the wire must be operated at the 60 degree rating, or less as the case may be. Due to the vintage of the equipment, and the standards at the time, I do not believe you will find such to be the case.

    Not one of the breakers is equal to or in excess of 100A, predate a requirement to slant rate for temperature, and are obsolete. UL testing requirements and standards were significantly different (less) at the time period (for both the breakers and panels; the temperature rise and other standards were not as they are today, limitations in the labeling must be especially respected in pre 70s panels - as requirements for testing and declaring buss bar and buss stab ratings were not prior or even as they were then.

    XO breaker production didn't stop due to lack of demand, tooling up and production a few times a year still occured years beyond the stop of production of load centers, it was the inability to pass more stringent testing & safety requirements for listing or classification.

    Judging from participation on other forums, SP has been exposed to such "fringe" information in the past, may have merely forgotten, but the discussion was not all-encompasing and was relevant going back to just the late 70s. R.M. has not grasped even the concept on load center equipment of that era and more recent. B.K. has a unique ability to contradict his own contributions within the same topic.

    For the OP, you might find this very general overview on the topic of capacity, somewhat helpful:

    Home Inspection and Building Inspections in Rochester NY by Warren Engineering: Electric Service Capacity

    Last edited by H.G. Watson, Sr.; 01-30-2011 at 09:51 AM.

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    Default Re: Rating of split buss panel.

    Quote Originally Posted by H.G. Watson, Sr. View Post

    Judging from participation on other forums, SP has been exposed to such "fringe" information in the past, may have merely forgotten, but the discussion was not all-encompasing and was relevant going back to just the late 70s.
    Man, I have to agree with some of the other members here. So many of your posts are filled with a ton of useless babble. You need to stop talking like an engineer and talk like a normal person.
    What is it with engineers and WAY over thinking EVERYTHING.

    I have ABSOLUTELY NO idea what the above quote means. Is it a compliment? An insult? What???



    The panel is 60+ years old. It's very old. Recommend evaluation by an electrician and move on. This relieves you of the responsibility.
    There is really no need to over analyze it with temperature ratings and such.
    Jeeze.


  20. #20
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    Default Re: Rating of split buss panel.

    If this were my house, I would immediate replace it in order to allow myself room for expansion, etc, and to allow for upgrade to GFT or Arc Fault breakers. Its easy for me, though, as a licenced electrician, but I would even recommend it for others.
    Its not an expensive upgrade, but it would help me sleep better.
    Norm


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    Default Re: Rating of split buss panel.

    Because there is a #4 Copper service line from the meter, there is 100 amp service into the structure. Regardless of how it is split and divided in any panel, there is still 100 amp service into the structure. The answer to the realtor and the buyer, is Yes. That said, this main panel is full. Nothing new can be added. If the buyer has plans to add new circuits, an upgrade will be needed. And of course, any upgrade will have to comply to current code.


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    Default Re: Rating of split buss panel.

    Quote Originally Posted by Jimmy Roberts View Post
    Because there is a #4 Copper service line from the meter, there is 100 amp service into the structure. Regardless of how it is split and divided in any panel, there is still 100 amp service into the structure. The answer to the realtor and the buyer, is Yes. That said, this main panel is full. Nothing new can be added. If the buyer has plans to add new circuits, an upgrade will be needed. And of course, any upgrade will have to comply to current code.
    Not if the meter can is rated 60 Amp. As has been pointed out, there is insufficient info from the OP to make the determination.

    A service includes all the wire and equipment from the point the utility attaches to the customer owned wire and equipment (POS) to the service disconnect. You don't know what the ratings are on the meter can, meter, or the service entrance wires.

    The size of the service is determined by the wire and/or equipment that has the smallest rating. So, if all the wire, the meter can, and the buss in the panel in question here all have a 100 or more AMP rating then you have a 100 AMP service. If any of the parts are rated at less, you don't. It doesn't matter what's available at the panel buss, it matters what the ratings are.


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    Default Re: Rating of split buss panel.

    You can argue what ifs until the cows come home, and speculate what the meter base may be rated at. This panel contains pretty close to 100 amps of circuits. It is fed by #4 copper leads. Arguing that the meter base may be rated at 60 amps is far fetched. It is not likely that #4 copper would fit into 60 amp connectors. It is not likely that a licensed electrician would wire a 60 amp meter base, with #4 copper. It is not likely that the utility would connect a meter to a 60 amp meter base, with #4 copper leads attached, and it is even less likely that a building inspector would allow a 60 amp meter base to feed a 100 amp panel. Now, if you want to argue that a homeowner installed a 60 amp meter base, and somehow convinced the utility to connect this installation without a building inspection certificate, then and only then, would you even speculate that a 100 amp panel could be connected to a 60 amp meter base.


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    Default Re: Rating of split buss panel.

    Quote Originally Posted by Jimmy Roberts View Post
    You can argue what ifs until the cows come home, and speculate what the meter base may be rated at. This panel contains pretty close to 100 amps of circuits. It is fed by #4 copper leads. Arguing that the meter base may be rated at 60 amps is far fetched.
    For a new person here you sure sound like you like to argue with someone who KNOWS A LOT MORE THAN YOU SEEM TO KNOW ... AND ... that person is correct and you are not.

    The size of the service is THE SMALLEST of the ratings of the components: the meter, the service entrance conductors, the panel rating, the main disconnect rating ... it does not matter what the higher ratings are, it is THE SMALLEST rating which matters.

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    Default Re: Rating of split buss panel.

    Quote Originally Posted by Jimmy Roberts View Post
    You can argue what ifs until the cows come home, and speculate what the meter base may be rated at. This panel contains pretty close to 100 amps of circuits. It is fed by #4 copper leads. Arguing that the meter base may be rated at 60 amps is far fetched. It is not likely that #4 copper would fit into 60 amp connectors. It is not likely that a licensed electrician would wire a 60 amp meter base, with #4 copper. It is not likely that the utility would connect a meter to a 60 amp meter base, with #4 copper leads attached, and it is even less likely that a building inspector would allow a 60 amp meter base to feed a 100 amp panel. Now, if you want to argue that a homeowner installed a 60 amp meter base, and somehow convinced the utility to connect this installation without a building inspection certificate, then and only then, would you even speculate that a 100 amp panel could be connected to a 60 amp meter base.
    Your assumptions are what gets people in trouble.

    The total of the AMP ratings of the individual breakers has nothing to do with what the panel is rated at or what it is supplied with.

    When was the last time you saw terminations on a meter or panel that didn't allow for larger wire to be used to take care of voltage drop? I've got a couple of old 60s out in the shed that will take #2 wire.

    You must not do much service work. I find panels with ratings over twice what the rest of the service is rated for on a regular basis. You live in a dream world if you believe every installation is inspected or the utility notified every time something gets changed. AND, this installation is from a point in time when many areas had no or very little in the way of inspections.

    I wouldn't be willing to state this is a 100 AMP service till I can see the whole thing, especially if you are likely to get sued if wrong. You are, however, more than welcome to send certification to the buyers that based on the information you got off this thread in a forum discussion that they in fact do have a 100 AMP service - I just want a bug in the lawyer's office when there's a problem.


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    Default Re: Rating of split buss panel.

    As I recall the limited testing, reliance on calculations, and self-certifications regarding the standards of that vintage,

    The UL rules and calculations for listing was based on a presumed heat generating load of 10A per pole per bus connection for ratings heat irrespective of the breaker's ampere rating or load calculations for the installation, for listing purposes, as I recall that load was for 3-4 hours with corresponding downtime to cool off.

    The majority of the calculations used for the early listing standards for panelboards and circuit breakers were faulty and actual tests and more stringent standards went into development. As I recall larger CBs and switchgears for distribution first developing very late 60s drafted, then the low voltage tougher standards into the early 70s. The effect of the federal laws developing OSHA etc. also played a part in it. I'm recalling the country averaging well over 1,000 deaths per year many electricians, working at panelboards or switchgear being a motivating factor, in addition to huge casualty lossess per year.

    As I further recall, the XO wasn't made in a size larger than 50A and sub bus designed for heat load breaker configuration UL standard to 50A. Limitations were five 120V per bar. The labeling would have maxed at 10 120V breakers on the submain total, five per bar using the at the time standard dictating application calculation of 10A per device per pole. With the 120/240 that has exceeded or overloaded the designed buss rating calculation and the panels vintage listing. If it were permitted to use the 120/240 2-pole breaker in that area (and it wasn't) - two of the 120V breakers would have to be removed. IOW 1-2p 120/240 (2xpoles per bar x10 = 20 per bar) plus 6 120V sp breakers total, 3 per bar (1xpolesx3breakers per bar = 30).

    It didn't and doesn't matter what the demand load calculation is for a 120V circuit on these buss bars, or if there is a 6A load - the installation rules and listing standards at the time used a maximum limit based on a 10A load implied per breaker per bar per pole rule - this 10A rule also compensated for the buss and materials of the breakers not damaged, misshapped even temporary by heat.

    I am also not recalling a sq D branded XO panelboard/enclosure greater than 50A rating L&A buss.

    I am also not fully convinced we see actual #4 CU, entering from the back wall of the enclosure. Argueably the incorrect replacements at the jumper lugs could be throwing me. 60A was the high end of norm this vintage. Insulation materials and temperature ratings/allowable ampacities NOT IN FREE AIR were quite different. IIRC PVC was just beginning to be used with nylon, rarely, at the time.

    I have doubts this installation meets the current FHA/VA program underwriting criteria.

    Last edited by H.G. Watson, Sr.; 01-31-2011 at 06:18 PM.

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