Main breaker

[GG]

In what year did the NEC make it a requirement to have a main breaker in a residential service panel? I see houses built in the 70's that do not have a main breaker.

 

[charlie b]

No such requirement exists, even today. The residential building will have to have a disconnecting means. But that need not be a breaker, indeed it need not even have overcurrent protection, and it certainly does not need to be a breaker in the service panel. There does have to be overcurrent protection for the panel. But here again that need not be a breaker at all, let alone a breaker in the panel itself. Is someone telling you that a main breaker is needed?

 

[OTT2]

In what year did the NEC make it a requirement to have a main breaker in a residential service panel? I see houses built in the 70's that do not have a main breaker.

Are you refering to a Split-Buss panel?

 

[GG]

Yes, an inspector here wants homes without a main breaker to have one installed. So in this picture if this was a panel in the garage of a house and it was fed from a meter base outside, the conductors supplying power to the panel do not need to be on a breaker or disco?

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[jumper]

You have a MLO main panel fed straight from a meter? That is only legal if you have 6 breakers or less.

 

[charlie b]

Yes, an inspector here wants homes without a main breaker to have one installed.

Does this inspector have a code reference to back up his "want"?

So in this picture if this was a panel in the garage of a house and it was fed from a meter base outside, the conductors supplying power to the panel do not need to be on a breaker or disco?

As I said earlier, there has to be both a main disconnecting means for the building and overcurrent protection for the panel. One way to achieve both goals is to put a main breaker in the panel. Another is to put an enclosed breaker or fused disconnect ahead of the panel. I suspect that some meter bases have a built in capability to achieve the same goal. Do you know if the particular installation under discussion has any such devices already installed?

By the way, is the house attached to this garage? If not, some additional requirements come into play.

 

[raider1]

Yes, an inspector here wants homes without a main breaker to have one installed. So in this picture if this was a panel in the garage of a house and it was fed from a meter base outside, the conductors supplying power to the panel do not need to be on a breaker or disco?

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They would need a service disconnecting means in accordance with 230.70 and 230.71.

Most likely the panel in the garage might exceed the distance with which the service entrance conductors could enter the building.

Also the panel appears to have more than 6 breakers installed and could not be counted as the service disconnecting means.

Chris

 

[mcclary's electrical]

Is the top left breaker a back fed main? I can't zoom in enough. If it's got a hold down kit, then it's legal. If that's not a backfed breaker, they got their inspection with 6 breakers. and added the rest later

 

[GG]

Is the top left breaker a back fed main? I can't zoom in enough. If it's got a hold down kit, then it's legal. If that's not a backfed breaker, they got their inspection with 6 breakers. and added the rest later

Sorry, that was not the panel Im actually talking about. Its just a picture I found online. The panel Im working on has 30 breakers and no disoconnect.

 

[GG]

Does this inspector have a code reference to back up his "want"? As I said earlier, there has to be both a main disconnecting means for the building and overcurrent protection for the panel. One way to achieve both goals is to put a main breaker in the panel. Another is to put an enclosed breaker or fused disconnect ahead of the panel. I suspect that some meter bases have a built in capability to achieve the same goal. Do you know if the particular installation under discussion has any such devices already installed?

By the way, is the house attached to this garage? If not, some additional requirements come into play.

The inspector did not quote a code reference, but I see now that 230.70 and 230.71 apply to this panel. This particular installation, and Im guessing the entire neighborhood, has no disconnecting means for the service conductors that enter the panel. Plus the panel has 30 breakers so its well over the 6 breaker limit. My next question would be how long has 230.70 been a requirement in the NEC, and was there even ever a time when the installation I described was legal to install?

If it has always been a code requiremenet Im trying to figure out how so many homes passed an inspection as I see this quite regularly.

Also, the house is attached to the garage.

 

[jumper]

My next question would be how long has 230.70 been a requirement in the NEC, and was there even ever a time when the installation I described was legal to install?

I just looked in my 1940 NEC Handbook and the rule exists there. Does that help?

If it has always been a code requiremenet Im trying to figure out how so many homes passed an inspection as I see this quite regularly.

How do you know that they were inspected?

 

[cowboyjwc]

Go to the FPN after article 230.71 which will send you to 408.36 and then go to exception No. 2.

Exception No. 2: For existing installations, individual protection for lighting and appliance branch-circuit panelboards shall not be required where such panelboards are used as service equipment in supplying an individual residential occupancy.

 

[GG]

Go to the FPN after article 230.71 which will send you to 408.36 and then go to exception No. 2.

Exception No. 2: For existing installations, individual protection for lighting and appliance branch-circuit panelboards shall not be required where such panelboards are used as service equipment in supplying an individual residential occupancy.

Well with that exception it looks like the panel is good to go as is. Thanks. Thats odd though, it says for existing panelboards. Since a panelboard requires overcurrent protetction would'nt the panel have been a code violation when it was originally installed to now be considered existing and not needing overcurrent protection?

 

[GG]

I just looked in my 1940 NEC Handbook and the rule exists there. Does that help?



How do you know that they were inspected?

1940, guess its been in there a while. I didnt know you could build a house without a permit, when did it become a requiremnet to get a building and electrial permit when doing construction anyway? Im wondering if building permits were required back in the 70's.

 

[jumper]

Well with that exception it looks like the panel is good to go as is. Thanks.

Hang on we are not done here.

 

[jumper]

Go to the FPN after article 230.71 which will send you to 408.36 and then go to exception No. 2.

Exception No. 2: For existing installations, individual protection for lighting and appliance branch-circuit panelboards shall not be required where such panelboards are used as service equipment in supplying an individual residential occupancy.

That does not relieve of the max 6 switch disconnect rule.

 

[cowboyjwc]

Hang on we are not done here.

Don't think I didn't see that coming. :grin:

 

[jumper]

1940, guess its been in there a while. I didnt know you could build a house without a permit, when did it become a requiremnet to get a building and electrial permit when doing construction anyway? Im wondering if building permits were required back in the 70's.

You never answered the question" Are these split bus panels?"

 

[jumper]

Don't think I didn't see that coming. :grin:

Of course.

 

[eprice]

1940, guess its been in there a while. I didnt know you could build a house without a permit, when did it become a requiremnet to get a building and electrial permit when doing construction anyway? Im wondering if building permits were required back in the 70's.

That will vary from state to state and from community to community. I believe there are some places even today where codes either have not been adopted, or are not being enforced. In these areas, permits and inspections are not required. I would guess that Chicago, New York, and other large cities were probably the first places to adopt codes and implement inspections. I don't know when this first occurred. All of the other places that require permits and inspections started doing so sometime between then and now