For an existing building, seven single-phase mains supplies with meter devices installed by the electrical company are supplying electricity into a same tenant installation. The tenant receives a single bill each month.

Regarding the NEC specifically, i would like to know, if there is admissible to feed all the single-phase mains into a single distribution panel with breakers and protections, of course keeping separated the sub-circuits, as per each mains.

I am thinking on a single distribution panel for the obvious convenience by the construction, the final owner and users.

This is a similar case than in a three-phase case, when each phase is kept separated as sub-circuits, and similar to single-phase and three-phase with an emergency system; all cases in which a single distribution panel is the standard usage.

Thanks in advance,

EDIT: The Rule of Six (NEC 230.71A) limits the maximum number of disconnects to six per service entrance conductors. Considering the building|tenant is unique, this is an argument for requesting the company to reinstall a single service conductor and a single meter device.

  • Where on Earth are you, and who's your utility?! Also, how did this come to be? – ThreePhaseEel Dec 8 '17 at 4:04
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    In the pictured example it appears that all three meters are supplied from one service drop which is single phase (split phase 120/240 V?), so I assume that in the question, all seven meters are supplied by one service drop. I further assume that the service from each meter goes to a separate panel. It seems that what the OP wants to know is can the seven meters somehow be replaced with a single meter, and the seven panels somehow be replaced with a single panel, right? What are the cable distances from the meters to the respective seven panels? – Jim Stewart Dec 8 '17 at 10:31
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    No, I'm sorry, this question is really unreadable and is confusing every answerer and several people are telling you that. Your refusal to give basic info like what nation you are in, asking about US NEC but giving all units in metric, is making you seem either dodgy or really dumb, and I don't think the second one is true. I am trying to communicate to you how these deficiencies are making you really frustrating to deal with. I really wish you'd make an effort to improve it, as it could be an asset if cleaned up. You'll get much better answers if you do. – Harper - Reinstate Monica Dec 8 '17 at 21:57
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    If you don't have the information at hand, that is totally understandble. I did a major revision of my answer. – Harper - Reinstate Monica Dec 8 '17 at 22:36
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    @hyprfrcb, I gather that the country that this property is in has single phase not split, so probably 220 V to 240 V 50 Hz, right? – Jim Stewart Dec 9 '17 at 16:31

First, you can have only one meter/service per occupancy (unless you have something really weird). An occupancy is a single tenant, within reason. For instance a single family home gets one service. If that house is later subdivided into four apartments, it could have four meters and four services, but the power company will be reluctant to provision all this, so they will insist on proof that the city authorized the subdivision.

Similarly, a large building subdivided into live-work spaces, workshops, studios or retail stores may be able to get a separate utility meter and service for each tenancy.

Alternately, the landlord can take one service, and fit his own "submeters" and then rebill the tenants.

So what happens when the 4-unit apartments are turned back into a single family home? Awkward. The power company may be able to bill them on one bill. Electrically, you have to live with it, and keep each service's hots, neutrals and grounds separate. If you've got four 60A services and want to fit a heat pump with a 70A aux heat, you've got a problem.

You can't feed one main panel from two meters. (unless the power company specifically wires you up that way, and remember, the point of demarcation isn't the meter, it's below the meter, and in that case, it would be on them). This would be paralleling without using equipment made for paralleling, and would raise huge issues for overcurrent protection, maintenance shut-off, and finding main panels able to support merging main feeds (you won't). And if any of the services are out of phase with each other -- KABOOM! That last is why even if you were do this harebrained idea, you'd want overcurrent protection before the merge.

What you can do is install one new, proper main service (e.g. 200A) with one main panel. Then later at your leisure, cut over each old panel to be a subpanel of the new main. If you are in Europe, the new main could be 3-phase and serve a single phase to each subpanel. So for instance, in that case, you'd provision your heat pump's 70A aux heat directly off the new main, bypassing the subpanels altogether. You could cut loads over to the new main at your leisure, and eventually deprecate the old panels. But --

Just to sanity check here, are you sure the building's best value isn't subdivided? If so, take care to arrange things so a rollback is possible. If so, the plan might be leave the subpanels intact, and go with submetering if that day ever comes.

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    Harper I put in systems regularly that would be similar to what the OP wants I agree they the OP could not directly tie the panels together if a 3 phase feeder but if a split phase feeder it could be done, commercial properties in my area regularly feed 1200 amps 240 and I know of larger but the cost of GFCI monitors at the service is a pain so we keep them below 800a. – Ed Beal Dec 8 '17 at 14:32
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    @EdBeal if you have GFCI monitoring on the meter, you are certainly not paralleling meters as OP wants, the GFCI detection would be tripping continuously. – Harper - Reinstate Monica Dec 8 '17 at 15:56
  • My question indicated, as in any three-phase distribution panel, and as in any mains plus emergency mains distribution panel, is that different phases do not contact each other. – Brethlosze Dec 8 '17 at 19:56
  • The subdivision argument is good. This is a single building and so, neither have an argument to leave seven panels for future subdivisions. If i would have seven houses or seven clear loads it would be clear for me and the question would be vane. – Brethlosze Dec 8 '17 at 20:02
  • If they were on different phases, i still keep the argument that three-phase circuits are most of the time dealt in a single distribution panel. And no repairmen are advised never to mix two different circuits, even in single-phase systems. So this argument still do not lead me to think having separated panels is the choice. – Brethlosze Dec 8 '17 at 20:06

The question is extremely confusing, but I will try to answer what I think you are asking. It appears that there is a SINGLE electrical service from the utility company coming into a main distribution panel, with feeders going out to a number of meters for tenants. These meters are provided by utility company for billing each tenant. Yes, this is very common and is standard for apartment buildings and small strip malls. What exactly is your concern?

Another configuration is to have a private sub-metering system where the sub-meters are owned by the properly owner and he bills the tenants. This is allowed only if the meters meet a certain standard (revenue grade), which most, if not all of them do. There must also be a master meter provided by the utility company in this type configuration which is used to bill the buiilding owner.

Hope this helps.

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  • The question is if the code allows one distribution panel per tenant, instead of one distribution panel per utility service, when the meters are owned by the company. Utility services in both case you mention is unique, which simplify greatly the situation, to decommisioning all redundant meters, and replacing them by a bigger one. I am stating there are several utility services, due to past project expansions. – Brethlosze Dec 8 '17 at 5:34
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    @hyprfrcb yes, tenants who pay his own power bill are considered an occupancy and are generally entitled to their own meter. In some industrial subdivisions like artist live-work arrangements in old warehouses, they may provide one service and then the landlord submeters. Are these submeters? – Harper - Reinstate Monica Dec 8 '17 at 21:45

This is not a code controlled issue. Most utility companies only provide a single service to a single building , unless there is some extremely unusual condition, such as service over 8000A, or if there is need for multiple voltage services coming into building. The only code concern would be tenant access to main disconnect(s) for each tenant so that tenant can turn off power in an emergency. The code has a limit of no more than 6 switches or breakers to shut off power to a facility. I don't recall in my 30 years as electrician even seeing more than 2 services in a building, even in an industrial facility - so the code does not anticipate or control such an issue.

In any case you cannot just bring all the services into a single distribution panel. The old services will need to be removed and replaced with a new properly sized service. Load requirement will need to be analyzed by qualified electrical contractor, as demand calculations can get very complicated if this is a large facility.

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  • I normally work with architects so, most of the projects i see have or will have several meters. But in this case the meters and the utility connections already exists. The code is very strict with the components inside panels both with single and three-phase, so i dont think this issue is free, or at least there should be some indication, but so far i dont know which one for saying this is ok or which one for saying to no-go. – Brethlosze Dec 8 '17 at 6:03
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    I see commercial buildings all the time that have multiple feeds, I am guessing some are 3 phase and some single phase, these would need to stay separate unless you feed the entire system with 3 phase and use transformers to create your single phase. The building could be rewired with 1 or 2 services eliminating all the redundant to you meters and service panels but be prepared for sticker shock this is going to be expensive. I usually try to keep my feeders under 800 amps so I don't have upsize wire to the breaker size and no GFCI monitoring on the mains. – Ed Beal Dec 8 '17 at 14:22

If the example you posted the link to is one of your sets of meters it is possible that it is a single feeder , we know the main service is tiny compared to most commercial multi tenant units I have worked on in the past I say this because of the small size of the feeder conduit coming in the top and the size of the 3 feeds going in the building. So in that case it would not be hard at all. If it is a 3 phase feed split between the services a transformer could be added and the seperate services fed from the transformer. This is where it gets sketchy if there is a second service drop. If fed from the same supply it could be done within code or the amperage was more than the utility normally provides a second drop can be done on 1 building at the same voltage/ phases etc. If 1 drop is split phase(240) and 1 drop is 3 phase you would still need 2 meters and distribution systems. Many of the buildings I have worked on in the past had 480 & 240 feeds for light industrial loads light commercial is usually 208/3 phase. And heavy industrial is 480/3 phase and the 240/120 or 208/3 phase is transformed from the 480. So yes it can be done but knowing what the service feeders are and there voltage would be needed to provide a complete answer.

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  • Appreciate your answer. I actually see electrical system adding panels for simplicity, but the number of panels increase per any repowering, in an ugly sequence. – Brethlosze Dec 8 '17 at 20:08

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