single dwelling calculation

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whitt

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I have ran into a problem this weekend that so far the people i have asked for help have given me conflicting information so hopefully you guys can help.
I have been doing the wireing for a relatives house after a mix up over money or something with the contractor so I have had to go back and rewire from scrach with existing wire that i have found problems in more than one circuit i had to fix but that is the least of my problems now. This weekend as i was showing up to work the HVAC contractor showed up to look around and the yard has been dug up after a while of chatting i found out they were installing a geo thermal unit and he told me it was the first one he has installed .as he was talking he mentioned the unit had a 20kw backup. I started thinking this was rather large. So when i got home i did a house calculation for a 2200 sq ft house with the 20 kw witch Iwas told backup is listed in the nameplate useing the 20 kw and i used some small kw's for the appliances and the motor which was my garbage disposal and since we dont have power yet i used 220v and 240v for line voltage at 220v i came up with 209a and 191a with 240v. I told the homeowner,which is a engineer for the federal gov, with this i need the real nameplates rating to do an accurate calculation needless to say he was less than wanting to help and laughed and said people dont have 400 amp services in a house this after he just mentioned he changed his range plans to have a big double oven and did not think much of it but after telling him like three times he said he would get around to it.
I am trying to help some one I also know i can turn the job down at any time if i dont feel it is safe and i truely believe in being ethical and will not continue if i feel this is unsafe.
Finaly to my question there is no fire marshall or inspector to answer to since this is outside the city limits in west virginia so this is solely up to me so if you have a calculetion that runs over 200a on a house, i know it will be between 200a and 250a , do you just refuse to instal this system make it mandatory to move up to a 400a, is is there consideration for aux backup hat because of the lack of use or is 200a the cut of period.
Any help please the only response i have got so far from masters or anyone else is hook it up if he is paying. That is not good enuf answer for me and i refuse to work like that
Thank you,Whitt
 
Re: single dwelling calculation

There are homes that have 400 amps.Maybe you could get by with a 200 and 100 double lugged meter.It seems he is maxing out the 200 and in time he will want to add things.Would exsplain this to him .There is a 225 amp panel and that would not add that much to cost.
 
Re: single dwelling calculation

Jim
What rated meterpan would you use with the 225 amp panel?

Whitt
I would leave the job now, it seems as though the first guy may have left for the same reason. Sounds like the HO wants what he wants for less :roll:

Pierre
 
Re: single dwelling calculation

I think Jim is right.

There are 320amp meters that are rated 400amp for Single family dwellings. This meter will allow you to install a large enough main and the panels you need.

http://www.hialeahmeter.com/sockets.htm

[ January 23, 2004, 12:26 AM: Message edited by: russ ]
 
Re: single dwelling calculation

The Milbank "K" series offers 400-600a residential meter bases.

The one we use here are rated a full 400a,and cost us about $130. They come with double barrel lugs,and are easy to work with.

Russell
 
Re: single dwelling calculation

The POCO where we work has a lot to say about services.
Services larger than 200 amp for homes now are required to be a minimum of 400 amps, with POCO approved meterpans ($525 for the meterpan), plus a few more restrictions. So a 400 amp service minimum price is around $2500 to $3000 in this area, depending on the particulars it could even go higher. I know that different jurisdictions permit different installations. For instance the Milbank meterpans are not permitted here.

Where ever Whitt is from, he should consult the POCO first before he gets deeper. It still seems to me the homeowner is the problem.

Pierre
 
Re: single dwelling calculation

The cost of the 400 (320) meter pan is somewhere around $100 that plus another panel 100 amp doesn't come near $2500.Sounds like some local poco are forcing the use of certain pan's (wonder why ).Regardless of the price if it calls for over 200 amps and you don't do it,then who will foot the bill when the 200 burns up or keeps tripping.Does sound like this guy wants to tell the electrician how to wire.Would at this point put tools back in truck and go home.He will find someone to do this his way,but won't be your headache when it fails.
If this is a relative just why were you not called in the beginning ?
Might check with Mr AC man as to why a 20 kw back up.Often they can lower this amount..In Fl (yes it gets cold here too )a 10 KW is usually enough for 2000 sq ft homes.I know WV does get cold

[ January 23, 2004, 09:21 AM: Message edited by: jimwalker ]
 
Re: single dwelling calculation

Thanks for all the replys and you are right jim walker to pack up and leave that s about where i am at. The question why i was not the first electrician called goes to my line of questions in west virginia especialy outside city limits it is not uncommon fo the builder ,framer contractor ,to do the wiring not to mention everything else as long as he has some sort of general contractors license with no other license or licensed workers. Our state or suburbs are not up to national standard when it comes to the NEC or local fire marshall but i here i has been worse and is getting better.
So in your guys honest opions any calculation that exceeds 200a needs a service rated higher. I know this question sounds stupid and is self explanatory but the response i get from local masters licensed that have not been trained like i have say it is fine to hook up like this because the backup heat never comes on, also what HVAC company says witch i dont agree with either so since no one i have spoke with directly agrees i just wanted to here from some of you guys that have to practice more stricter regulations would ever exceed the 200amps for an backup system. And honestly i would feel a lot beteer since i am a young electrcian tryng to do whatr is right that is my main goal and haveing guys with 15 plus years around here saying i am over reacting and there are no need for calculations like this in the first place uless you are working in huge homes.
thank you whitt
 
Re: single dwelling calculation

If they are so sure the back up never is needed then ask them not to install it.That way there is no problem.I have seen some states and towns that are far from code compliant.Maybe your generation of electricians can help.
 
Re: single dwelling calculation

Thanks for the info on the 320 pan this is a first for me and i asked around today and no one i have spoken to in the residetial feild has ever used one most never herd of one so i am going to check it out for future reference at the least to see if i can use it here without any problems i have been told that in some cases contractors have had to add ct's to 400a services for safty reasons for local power company employes around the meter dont know if this is fact this was told by an electrical contactor to me today.not to many 400a services around here they are few for residential But i will find out everything i need to know when i look into this . Could someone help me out with the leters POCO i a not familier with the term.
 
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