I’ve got this house figured up, but I’m still looking for some input.(anyone?)
If I figure it up standard: 186 amps If I figure it up optional: 166 amps
A little bit of a variation. Is there a better way to figure this than what the NEC has laid out in the book? Obviously a lot of room is there for someone to use some discretion.
If I plug some numbers in a little different I get as much as 193 amps. Now it is my personal feeling that these bigger custom homes have way more ampacity than will ever get used. I’ve done them with 600 amp services before. I would bet those service entrance conductors never see a day over 150 amps.
So I lean heavily toward wanting to tell this guy, no problem, you still have room for another oven if you want. But I’d feel better crunching the numbers using a different engineering method, if one exists. Any suggestions?
Computing by code is the minimal standard. Go for the 400 Amp. It is my experience that owners of these custom homes count the size of the service as a matter of pride. "My house has a bigger service than your house". You want the job? Tell the owner according to your calculations, he will need to upgrade to 400 Amps before the decade is out, so you suggest he has you install 600 Amps, just to be safe. (with an automatic back-up emergency generator, too)
George This is an existing house (20 years old). The problem is that the difference is quite large between leaving it as is, and a new 400 amp service. The city will make us put the new meter on the side of the house which makes it tricky getting through the finished basement ceiling to refeed the existing panel and finding an appropriate spot for the new panel. I’m going to throw out $5000 as a rough idea (maybe $6000).
Earl, I admire your zeal for salesmanship. Yes, if it were new construction I’d push toward the 400 for obvious reasons, mainly being that for the extra cost now verses doing it later, you’d be silly to think there was any good reason not to go 400.
I don’t care either way about getting the job due to the PITA factor. But if I do sell him a 400 amp upgrade, I would rather that while I grunt, sweat, and scratch my head, it would help to feel like I’m doing this because it really needs it.
I just don’t feel convinced that the NEC’s load calc. method is appropriate for these bigger homes. And maybe that’s based on what we see the POCO doing (I know I’ve that discussion around here before) – 42,000 VA worth of calculated load fed off a 25KVA transformer with 5 other homes.
Sparky, I looked back to July posts and didn’t see anything. It’s too easy to get distracted around here. I’ve only been here a few days and I’ve spent hours and hours looking at what people are saying. Should I expect this number to go up or down. I hope down once I get up to speed.