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#2736 - 07/22/01 10:06 AM Overkill? Maybe. But........
glenn35 Offline
Member

Registered: 07/21/01
Posts: 48
I would like an opinion on a service I am helping my cousin install.

He is building a 2500 sq ft house and I recommended to him to install a 400A service with parralel 4/0AL triplex underground wire.

First let me tell you that I am not an electrician but a lineman. My reasons for 400A service is not that I beleive he would ever come close to maxing out the 400A nor probably even a 200A service, but the length of the run from the service entrance to the power comp. trans.

The run is about 150'-160'. Quite a long ways in my opinion, and a good chance for voltage drop. Even if that drop is only for a few seconds while the A/C compressors kick on. So the main reason for the 400A service was to increase the wire size of more than a single 4/0AL. And down here maximum wire size for 200A is either 4/0AL or 3/0cu.

Copper is way too much money and too heavy in my opinion.

The service will underground from the house with two 2" conduits and riser up the power comp's trans pole.

I always figure that too much is better than not enough. I mean why not? The trench is dug and ......

thanks

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#2737 - 07/22/01 11:06 AM Re: Overkill? Maybe. But........
golf junkie Offline
Member

Registered: 04/22/01
Posts: 511
Loc: York, NE
Standard procedure for this house would be 250mcm AL-USE if voltage drop is a concern.

The only reason to to go higher would be a larger home or all electric with a large heating/cooling load.

GJ

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#2738 - 07/22/01 11:48 AM Re: Overkill? Maybe. But........
Bill Addiss Offline
Member

Registered: 10/07/00
Posts: 4196
Loc: NY, USA
Glenn35,

It does sound like a bit of overkill to me. By way of comparison, the underground service installed by the utility here (LI, NY) for 200A service is only 1/0AL ! and distances over 100' are common. One 4/0 would be twice the size of our 1/0 for the same size service. That would probably be acceptable if there is no chance of ever needing over 200A service.


Bill

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#2739 - 07/22/01 12:19 PM Re: Overkill? Maybe. But........
sparky Offline
Member

Registered: 10/18/00
Posts: 5545
Glenn;
if the chief complaint is 'flicker factor' i'm sure there are more economical ways to approach this than service size.

anyways, stick around, it's good to have a linesman on the BB


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#2740 - 07/22/01 08:57 PM Re: Overkill? Maybe. But........
glenn35 Offline
Member

Registered: 07/21/01
Posts: 48
 Quote:
Originally posted by golf junkie:
Standard procedure for this house would be 250mcm AL-USE if voltage drop is a concern.

The only reason to to go higher would be a larger home or all electric with a large heating/cooling load.

GJ


Yes that was the original plan to use 250MCM AL , but I tried calling about a 100,000 electrical suppliers and all had the same answer. HUH!! Well we would have to special order that. We don't stock that. They couldn't even give me a price range for the stuff.
Well it is all in the ground now and only thing left is putting the risers on the pole.

Thank goodness for 4x4 trenchers!!

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#2741 - 07/22/01 09:07 PM Re: Overkill? Maybe. But........
glenn35 Offline
Member

Registered: 07/21/01
Posts: 48
 Quote:
Originally posted by Bill Addiss:
Glenn35,

It does sound like a bit of overkill to me. By way of comparison, the underground service installed by the utility here (LI, NY) for 200A service is only 1/0AL ! and distances over 100' are common. One 4/0 would be twice the size of our 1/0 for the same size service. That would probably be acceptable if there is no chance of ever needing over 200A service.


Bill


They allow 1/0 URD for 200A service!! THats outrageous. That barely compares to my #2 AL for my 100A service and it only runs about 40' to a URD pedestal. And when my one A/C kicks on its like...."Dang circuit must be operating again."
In my earlier post I said that the mAx for 200A svc was 4/0AL or 3/0cu. Well that is not what I meant. It is required for 200A svc. No bigger , no smaller.

Now for OH svc then yes we do install 1/0 svc drop, but the SE is required to be 4/0AL or 3/0cu.

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#2742 - 07/22/01 09:20 PM Re: Overkill? Maybe. But........
silverbk Offline
Member

Registered: 02/24/01
Posts: 61
200 Amp service is more than sufficient for a 2500 sq foot house. I have done much longer services in much larger houses without voltage drop. In fact even on the longest ones it's hard to measure any appreciable drop ConEd is too good. With 4 acre zoning in some towns I have wired some pretty big spreads.

Copper makes for a better job and may be cheaper than doing two seperate runs of aluminum. Most electricians here would use 4/0 AL. You also have the added cost of the 400 amp meter socket and panel, they are ct cabinet style and exponentially more expensive than a 200 amp setup. If you are hiring an electrician you will also have about 1/3 more labor cost with a 400 amp service.

As far as the ac units most houses here use at least two compressors for different zones. Unless they both start at the same time (unlikely) flicker should not be a problem. A properly balanced load helps this condition.

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#2743 - 07/22/01 10:17 PM Re: Overkill? Maybe. But........
Bill Addiss Offline
Member

Registered: 10/07/00
Posts: 4196
Loc: NY, USA
glenn35,

An AC kicking in on a 4/0 or even a 1/0 circuit is going to look a bit different than your #2.

Have you asked any of the local Utility planners what they think?

Bill

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#2744 - 07/22/01 10:18 PM Re: Overkill? Maybe. But........
glenn35 Offline
Member

Registered: 07/21/01
Posts: 48
Well as for 200A cu.svc being cheaper than parrallel 4/0 400A svc I'll have to say no. Actually the cost was about equal.

Actually AL is a better deal because with it I (cousin) get a larger service. And the power company supplies the meter-can so there is no additional cost there.

So if he ever wants to open a small amusement park in his backyard then he should have no problems. HEHEHE

We (power company) had a guy that his electrician had installed a 200A 4/0 AL underground svc that ran about 200'-225'. Voltage at the trans was around 120 or 122. By the time it got to his house and under full load he had less than 110V. They somehow got it approved for him to install 4/0 cu. and we actually hooked it up. After I connected it and checked voltage I was getting 120V at the meter without load. I hope that solved his problem. As far as I know he hasn't called back to complain about low voltage.

[This message has been edited by glenn35 (edited 07-23-2001).]

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#2745 - 07/22/01 10:26 PM Re: Overkill? Maybe. But........
glenn35 Offline
Member

Registered: 07/21/01
Posts: 48
 Quote:
Originally posted by Bill Addiss:
glenn35,

An AC kicking in on a 4/0 or even a 1/0 circuit is going to look a bit different than your #2.

Have you asked any of the local Utility planners what they think?

Bill


Bill,
Yes actually I did talk with a power consultant and he pretty much agreed with me on paralleled 4/0. He said that we(power comp)only run our 350MCM AL a max of 140' due to voltage drop. We use 350MCM to run from a padmount to a pedestal which can serve 4 houses. But usually these houses are small to medium and their drops only about 50-60'from pedestal.

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