# 30 amp ?



## ralph (Apr 6, 2008)

Has anyone ever installed a 30 amp service ? I think ive got a situation where I might have to, but I dont know if thats allowed. I thought 60 was this minimum ?


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## MDShunk (Jan 7, 2007)

Yes, hundreds of small apartments. 

Billboards.

Traffic signals.

Cable TV amplifiers. 

Hurricane sirens.

(edit: Hey, this was my post #10,000)


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## Shockdoc (Mar 4, 2010)

I thought 100 amp is the minimum NEC. Special exception to traffic signals, signs, streetlighting and so forth.

But you can always cheat, instal 100 amp riser, meter and main in 4ckt panel, exit w/ 30 amp to wherever.


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## 480sparky (Sep 20, 2007)

Shockdoc said:


> I thought 100 amp is the minimum NEC. ........


100a minimum _rating_ for dwellings. 230.79(C).


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## MDShunk (Jan 7, 2007)

Shockdoc said:


> I thought 100 amp is the minimum NEC. Special exception to traffic signals, signs, streetlighting and so forth.
> 
> But you can always cheat, instal 100 amp riser, meter and main in 4ckt panel, exit w/ 30 amp to wherever.


100 amp is the minimum service size for a single family dwelling. In apartment buildings, it's very very common to have the metered feed to each apartment fused as much less than 100 amp. An apartment in a building full of apartments is not a single family dwelling.


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## Shockdoc (Mar 4, 2010)

MDShunk said:


> 100 amp is the minimum service size for a single family dwelling. In apartment buildings, it's very very common to have the metered feed to each apartment fused as much less than 100 amp.


The norm wev'e installed is 60 amp. However no utility company will tie in a 30 amp service unless it is part of a multi metering system.


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## 480sparky (Sep 20, 2007)

Years ago, it was a common question for, and I will quote it here, a 'roadside fruit stand', to be included in the electrical tests. A couple lights & receps, and it came to a 30a service.


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## MDShunk (Jan 7, 2007)

Shockdoc said:


> The norm wev'e installed is 60 amp. However no utility company will tie in a 30 amp service unless it is part of a multi metering system.


No utility system? Maybe none of yours, but I can say that's flatly untrue for all utility systems. I probably do 4 to 6 30-amp services a year, and just leave #10 hanging out of the weatherhead. They have crimps for that, since they tap the #12 tails for streetlights onto the larger ACSR all the time.


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## Shockdoc (Mar 4, 2010)

MDShunk said:


> No utility system? Maybe none of yours, but I can say that's flatly untrue for all utility systems. I probably do 4 to 6 30-amp services a year, and just leave #10 hanging out of the weatherhead. They have crimps for that, since they tap the #12 tails for streetlights onto the larger ACSR all the time.


None out here, LIPA requires us to use a 200amp bypass meterpan on a freakin sign. Those that you are doing, are they structures or fixed equipment?


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## MDShunk (Jan 7, 2007)

Shockdoc said:


> None out here, LIPA requires us to use a 200amp bypass meterpan on a freakin sign. Those that you are doing, are they structures or fixed equipment?


Okay, so use a 200 amp bypass meter can. No big deal. You can still put #10 in your riser, unless they have some silly rule against that.


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## Shockdoc (Mar 4, 2010)

MDShunk said:


> Okay, so use a 200 amp bypass meter can. No big deal. You can still put #10 in your riser, unless they have some silly rule against that.


They do, minimum of 60 so we add a SP 20 breaker and timeclock off of it.www.LIPA redbook


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## MDShunk (Jan 7, 2007)

Shockdoc said:


> They do, minimum of 60 so we add a SP 20 breaker and timeclock off of it.www.LIPA redbook


Figures. 

Luckily for the rest of the world, we don't have to suffer LIPA's dumb rules.


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## MDShunk (Jan 7, 2007)

The OP bailed out on us. He must be scared. :laughing:


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## Shockdoc (Mar 4, 2010)

Much of this topic goes by local utility provider rules over NEC. I'm constantly replacing aging services for a trailer park where some are single but most are stacked. They are requiring me leave my meter at 100 amps and then downsize to sixty after my main. They violated me on the 60 amp main.


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## Shockdoc (Mar 4, 2010)

MDShunk said:


> Figures.
> 
> Luckily for the rest of the world, we don't have to suffer LIPA's dumb rules.


You're lucky, you're living in one of the better states. I hate NY.


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## McClary’s Electrical (Feb 21, 2009)

The 100 amp dwelling rule is for the disconnect size, not the service size. 
Just sayin......


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## MDShunk (Jan 7, 2007)

mcclary's electrical said:


> The 100 amp dwelling rule is for the disconnect size, not the service size.
> Just sayin......


Yeah, but that's still "single family dwelling", which an apartment in a multi-family dwelling is not. But good point, just the same. You could potentially have a remote service for a group of single family dwellings, in which case each disconnect to each dwelling would have to be at least 100 amp, but the service would probably be in the hundreds or thousands of amps.


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## dieselram752 (Jan 23, 2008)

I was allowed to install a 30 amp 120 volt service a few years ago:001_huh:.
The meter was a standard 2 pole type but poco jumped out 1 leg to neutrel somehow to make it meter proper?
It was for 2 sign lites and only 120 was available in the nearest ungerground pit said poco.
Wasn't my idea just did what the poco engineers and local AHJ told me to.
I still scratch my head cause it seemed odd.


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## MDShunk (Jan 7, 2007)

dieselram752 said:


> I was allowed to install a 30 amp 120 volt service a few years ago:001_huh:.
> The meter was a standard 2 pole type but poco jumped out 1 leg to neutrel somehow to make it meter proper?
> It was for 2 sign lites and only 120 was available in the nearest ungerground pit said poco.
> Wasn't my idea just did what the poco engineers and local AHJ told me to.
> I still scratch my head cause it seemed odd.


Every once in a blue moon, I'll still run into an old house served with a 30-amp, 120V service. I've never seen a new 120V service, however, but don't doubt that they exist. There's diagrams of them in some of my PoCo's rules books, but I've never had a need or occasion to install one.


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## McClary’s Electrical (Feb 21, 2009)

MDShunk said:


> Every once in a blue moon, I'll still run into an old house served with a 30-amp, 120V service. I've never seen a new 120V service, however, but don't doubt that they exist. There's diagrams of them in some of my PoCo's rules books, but I've never had a need or occasion to install one.


 

Yes, and remember, whenever you're doing a service upgrade on a house that originally had a 120 volt service,You need to be VERY careful of any three way switching. You can easily end up with 240 volt on a light bulb switched from two locations.


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## TOOL_5150 (Aug 27, 2007)

MDShunk said:


> Every once in a blue moon, I'll still run into an old house served with a 30-amp, 120V service. I've never seen a new 120V service, however, but don't doubt that they exist. There's diagrams of them in some of my PoCo's rules books, but I've never had a need or occasion to install one.


There are still quite a few in the bay area here that have 120v/30a services.

~Matt


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## MDShunk (Jan 7, 2007)

mcclary's electrical said:


> Yes, and remember, whenever you're doing a service upgrade on a house that originally had a 120 volt service,You need to be VERY careful of any three way switching. You can easily end up with 240 volt on a light bulb switched from two locations.


Which is sometimes the case with a stairway light. 30-amp, 120-volt services normally had just two fuses. The "downstairs circuit" and the "upstairs circuit". Or, the "kitchen circuit" and "the rest of the house circuit".


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## Shockdoc (Mar 4, 2010)

mcclary's electrical said:


> Yes, and remember, whenever you're doing a service upgrade on a house that originally had a 120 volt service,You need to be VERY careful of any three way switching. You can easily end up with 240 volt on a light bulb switched from two locations.


The old k&t method of using local feeds as travelers and a common red to the light. That's rare but in existance when fed from two circuits


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## amptech (Sep 21, 2007)

I wired a seasonal RV park once where every site had its own meter. All of the sites were 120V. The park owner had bought all of the RV pedestals and meters for each one. Hialeah Meter Co. supplied the meters. Their website has all of the diagrams for wiring 240V meters to serve and correctly meter 120V. www.hialeahmeter.com.


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## ralph (Apr 6, 2008)

480sparky said:


> 100a minimum _rating_ for dwellings. 230.79(C).


 . Christmas lights for the county. POCO has no power except streetligts near by. said to aim for the last one, but only plan on 30 amps.


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## bobelectric (Feb 24, 2007)

MDShunk said:


> Yes, hundreds of small apartments.
> 
> Billboards.
> 
> ...


Yay! You get a box of chocolates!


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## frenchelectrican (Mar 15, 2007)

TOOL_5150 said:


> There are still quite a few in the bay area here that have 120v/30a services.
> 
> ~Matt


 
I have couple of 127V 32A service in few locations in France and the last count in Paris is 15 left on this service.

Merci.
Marc


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## wayne g (Nov 28, 2010)

You do not indicate what the 30 amp service is for. You are right the minimum is 60 amps, but keep in mind there are a few exceptions to the rule, what is this 30 amp service for. If this is for residential forget about it.

Still don't know what the service is for. If its residential install a 100 amp service, then you can put your 30 or 2 15 amp circuits into this new panel and you would be covered for furture expansion with plenty of spare circuits.


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## Dennis Alwon (May 9, 2009)

Why is everyone saying that the minimum is 100 or 60 amps. Look at 230.79(A)- if there is one circuit you could have a 15 amp service. If you have not more than 2 circuits then you could use a 30 amp service (230.79(B)). Of course, this only states disconnect size as mentioned earlier, but if we could have a 30 amp disconnect then the service would not need be greater.


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