5' rule

[Ambient44]

Hello,

Chicago electrtical code has a rule for service enrtrance conductors having a disconnecting means within 5' of the entrance to a building or structure, is the NEC rule the same and if so what is the article that specifies this code?

Tom

 

[iwire]

Welcome to the forum

The NEC does not have a 5' rule.

The NEC section that applies is 230.71(A)(1).

 

[Ambient44]

Thanks Bob,
230.71 (A) (1) Maximum Number Of Disconnecrts?
Doesn't seem to apply, Is there an article for disconnecting means for unfused conductors in relation to where they enter the building?
Tom

 

[iwire]

Tom, that is the section that applies.

Check out the last sentence.

It requires the disconnecting means be 'nearest the point of entrance of the service conductors.

 

[Ambient44]

Does 230.91 Location apply,
"The service overcurrent device shall be an intgral part of the service disconnecting means or shall be located immediately adjacent thereto."

 

[don_resqcapt19]

The code reference should be 230.70(A)(1). The meaning of this rule is subjective, and I take a very strict reading of it. My reading says that no amount of service conductor is permitted inside the building, other than what is within the service disconnect enclosure.

 

[Ambient44]

Thank you!
230.70 (A) (1)

 

[Twoskinsoneman]

Tom, that is the section that applies.

Check out the last sentence.

It requires the disconnecting means be 'nearest the point of entrance of the service conductors.

I've always found this rule to be peculiar. Seems like unprotected wires, especially with a very high available fault current, entering into a house would be frowned on...

 

[al hildenbrand]

Tom,

There are three sources for the exact distance limit, that I am aware of.

1. The supplying power company service rules. And those may even vary if the company is large. My PoCo covers a bunch of states and has multiple sets of "rules".
2. Local ordinance governing electrical installation.
3. The Electrical AHJ may even set the length.

In the area I work, there is a history of the distance gradually changing, and a history of exceptions to the general maximum distance.

 

[Twoskinsoneman]

The code reference should be 230.70(A)(1). The meaning of this rule is subjective, and I take a very strict reading of it. My reading says that no amount of service conductor is permitted inside the building, other than what is within the service disconnect enclosure.

This is a good way to look at it. I wish it was worded more strictly.

 

[wbalsam1]

This is a good way to look at it. I wish it was worded more strictly.

Have any bad experiences with SE Cable being an excessive length within a building and as a direct result being additionally more dangerous that you'd like to share?:smile:

 

[iwire]

This is a good way to look at it. I wish it was worded more strictly.

Before that happens I would like to see more substantiation then 'it just seems wrong'. :smile:

If history shows little problem with the rule as it is I think it would be wrong to change it.:smile:

 

[amptech]

The code reference should be 230.70(A)(1). The meaning of this rule is subjective, and I take a very strict reading of it. My reading says that no amount of service conductor is permitted inside the building, other than what is within the service disconnect enclosure.

I have done several services in buildings where the service conductors are ran in PVC coated rigid under the 6" slab and stub up out of the slab 36" and terminate in a MB load center. Are you saying you wouldn't be comfortable with the 36" of rigid containing the service conductors between the concrete floor and the panel?

 

[iwire]

I have done several services in buildings where the service conductors are ran in PVC coated rigid under the 6" slab and stub up out of the slab 36" and terminate in a MB load center.

Those conductors are still 'outside' the building until the come up through the floor. You could even run the service conductors 100' into the building using PVC conduit run inside if you encase those conduits in at least 2" of concrete.

See 230.6

 

[amptech]

I agree, but Don said any service conductor not inside the disconnect enclosure and that 36" above the concrete is inside the pipe but not yet in the enclosure. That 36" isn't considered "outside" once it comes out of the slab.

 

[electricmanscott]

This is a good way to look at it. I wish it was worded more strictly.

The way it's worded gives some wiggle room and allows common sense to be used when determining where a disconnect shall be located. With millions of services going into dwellings without an outside disconnect I think we'd know if this was a real problem. I say it isn't.

 

[don_resqcapt19]

I agree, but Don said any service conductor not inside the disconnect enclosure and that 36" above the concrete is inside the pipe but not yet in the enclosure. That 36" isn't considered "outside" once it comes out of the slab.

I think that I would be comfortable, but my reading of the code wording does not permit that 36" of PVC coated rigid conduit.

 

[76nemo]

I'll try to get a few pics for you Don that would make your skin crawl.

 

[Bulldog1401]

service entrance conductor length

service entrance conductor length

I think Iwire is correct in his interpetatin of the code. I also think that it should be rewritten to eliminate the "wiggle Room" currently allowed. I would think that a disconnect prior to the entrance of conductors into the building would be a safer way to do the install. I think it should be required.

Unfortunately, while the electrician will decide the "wiggle Room" issue on the side of safety, the builder will use it to cheapen the installation, "as long as we can get it to pass the inspector".

If you could eliminate the grey area. it would help to keep the builders honest.

 

[JWCELECTRIC]

NEC always has gray areas open for interpertation, They can't decide so they leave it up to the engineers, electricians, and local AHJ to fight it out. Then they then might get it right on the next issued code book.

What happens when a building has a 2000a, service? Install a 2000a nema 12disconnect switch on the outside before you enter to the main gear. Makes no sence. The rule is fine as it is, or NEC should set a distance, if that can't be met due to limitations, then it should be subject to the local AHJ.

- JWC