Main breaker in seperate enclosure

[mivey]

I will look for the comments on that PI later.

Cool! Thanks!

 

[kwired]

From the PI Jumper quoted: "This proposal seeks to require the installation of a utility external AC disconnect at the location of the meter on the exterior of the structure."

I have worked on many dwellings on farms or other rural locations that don't have a meter on the house. There usually is a site isolating device of some type where the meter is located though.

I have done a couple larger dwelling service dwellings that have CT metering at the transformer and many non dwelling services, mostly because there is only one customer served by that transformer.

 

[mbrooke]

Found it: Public Input No. 4224-NFPA 70-2014

(1) Readily Accessible Location.
The service disconnecting means shall be installed at a readily accessible location either outside of a building or structure or inside nearest the point of entrance of the service conductors.

( A ) Where installed on one family and two family dwellings, the service disconnecting means shall be installed outside the structure at the nearest point of entrance of the service conductors.

Statement of Problem and Substantiation for Public Input
Statement of Problem

Access to the service disconnecting means for first responders is very challenging when the disconnect is installed in a basement. Additionally with the incorporation of distributed generation such as PV or energy storage devices, the lack of access to safely securing the power generation to a residence from the exterior is made even more challenging.

The installation of a utility external service disconnect is a common practice in many areas of the country, including corrosive coastal environments, and should be provided in the code to ensure the safety of first responders when service disconnection is required in an emergency

This proposal seeks to require the installation of a utility external AC disconnect at the location of the meter on the exterior of the structure.
Submitter Information Verification
Submitter Full Name: Matthew Paiss
Organization:
Affilliation: International Association of Fire Fighters
Street Address:
City:
State:
Zip:
Submittal Date: Thu Nov 06 15:09:10 EST 2014

Committee Statement
Resolution: This requirement is onerous and not necessary. The hazard in a one or two family dwelling than it is not greater than in a multi-family dwelling or commercial building. The statement relative to environmental impact on exterior service disconnects is incorrect and in fact there are many instances where exterior disconnects do not operate when utilized due to the effects of the atmosphere on the disconnect. The submitter has not presented and factual data to support this requirement. Onsite power production sources have their own requirements relative to disconnecting means, anti-islanding features and proper placarding and notification relative to their presence on the property.

The committee statement is correct. And I would further add an exterior disconnect is 1. a design issue which is not the subject of the code and 2. The possibility of being tampered with by unauthorized persons.

 

[mbrooke]

What you say is true and yet over simplified. Outside disconnect is not required "if" we wish to place the panel with main nearest the point of entrace of service conductors.

That's why I can go in a sub-division of 5 thoundand homes and everyone of them will have a meter main combo. The may have figured that it was more cost effective to place the panel at a better location to feed branch circuits.

I didn't make myself clear when I said required. I should have said required because of panel location ( which does give them a choice ). I kind of assumed that people would know this.

Well, this is going of topic... but I remember a study done by the NFPA that said most breaker failures occur where breakers are installed outside.

 

[user 100]

Well, this is going of topic... but I remember a study done by the NFPA that said most breaker failures occur where breakers are installed outside.

Which imo, is another design issue- I've said this before here, but I hope that any code section that does away with ext breakers never sees existence and ditto for any extra special weatherizing shield scheme type of thing. We've already got sections (all throughout 300,312,and 408 among others) that when applied effectively prevent problems with ext panels- most outside jobs will be fine.

Ok, now back to regular programming.

 

[norcal]

Well, this is going of topic... but I remember a study done by the NFPA that said most breaker failures occur where breakers are installed outside.

Here in CA, most residential panels are installed outdoors, and I would almost willing to bet that there are more varied climates then other states, coastal, desert, snow, etc., doubt it's that much of a problem.

 

[jumper]

Here in CA, most residential panels are installed outdoors, and I would almost willing to bet that there are more varied climates then other states, coastal, desert, snow, etc., doubt it's that much of a problem.

Agree.

 

[mbrooke]

Here in CA, most residential panels are installed outdoors, and I would almost willing to bet that there are more varied climates then other states, coastal, desert, snow, etc., doubt it's that much of a problem.

I agree, but its still the designer's choice.

 

[iwire]

Pretty sure the utility in CA requires outside disconnects already. At least in some case, I have seen the requirements posted on these forums before

 

[mbrooke]

Pretty sure the utility in CA requires outside disconnects already. At least in some case, I have seen the requirements posted on these forums before

Ahhh, did not know this. That would make sense now, thanks you!

 

[gadfly56]

Pretty sure the utility in CA requires outside disconnects already. At least in some case, I have seen the requirements posted on these forums before

I have the same recollection.

 

[peter d]

Pretty sure the utility in CA requires outside disconnects already. At least in some case, I have seen the requirements posted on these forums before

I believe that it's a EUSERC requirement you're referring to and it applies to just about all western states that have adopted EUSERC.

 

[iwire]

I believe that it's a EUSERC requirement you're referring to and it applies to just about all western states that have adopted EUSERC.

No, there where discussions of CA services, specifically the practice of running the service conduit inside the wall cavity.

Someone posted one of the power company spec sheets and it showed the service conduit going directly into an exterior meter main.

 

[peter d]

No, there where discussions of CA services, specifically the practice of running the service conduit inside the wall cavity.

Someone posted one of the power company spec sheets and it showed the service conduit going directly into an exterior meter main.

Alright, but I still stand by my statement that it's a EUSERC requirement, at least for residential services.

 

[iwire]

Alright, but I still stand by my statement that it's a EUSERC requirement, at least for residential services.

Wouldn't that be the same as NESC, a standard they can chose to ignore or follow at will?

 

[peter d]

Wouldn't that be the same as NESC, a standard they can chose to ignore or follow at will?

That I don't know, perhaps Norcal can chime in since he is an expert in that area. I'm sure he'll correct me if I'm wrong, but I believe EUSERC came about as a way to unify the standards of western poco's, so there would be no reason to opt out of EUSERC. It's a standard based on a cooperation of multiple utilities rather than some boiler plate standard that may or may not be adopted.