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he's got 380 local utility approve-able amp capability available in that pipe/ aka 400 amp service adjusted for voltage drop IF they upgrade to max out the wire size for the pipe...

while there are often too many houses on the same transformer, there's no sense in planning for a lemon to save a few bucks. That pot would prolly be fine for the house, but for the house and intended shop (which is even further from the source) why under-rate things now?
 
I don't know how PG&E is but in some times if a customer is having power quality issues, the line crew responding to the trouble call will just upgrade the transformer at no cost to the customer. If you tell the power company you are upgrading they will have you fill out a load sheet and you pay for the upgrade. Usually they figure 12.5 KW load per residence, unless it's a 400 amp service. Since they only make a 10 kva transformer and the next size is 25 kva transformer they will spec a 25 Kva transformer. I hope this helps.
 
12.5 kva is only 75 amps of 240 volts...he's already informed the utility of his intent. I don't think the 10 kva would do his shop, let alone the house and shop...10 kva is only 50 amps...I had a client who light off his 15 horse compressor and blew the diodes in his 30 KVA onan...just food for thought...less is NOT moar in the world of watts and amps...
 
I get what you are saying and I agree, power companies overload their equipment and that is business as usual. Last week we were doing backyard pole change outs, the old pole had a 25 Kva transformer with 1/0 aluminum feeding 9 houses the houses had 100 and 200 amp panels. No one was complaining, we upgraded to a 75 kva pot.
 
none of those city rats were running 7.5 horse compressors or 50 amp welders while the boss was inside enjoying the AC while baking a turkey dinner, were they? apples and oranges...
 
Your right, just 9 families all getting off work at the same time and kicking on all of their appliances at the same time during peak load for the past 50 years on that same little transformer.
 
I hear ya it can work, but it's not the way to plan...this isn't just about quantity of electricity, but also and maybe moreso, about QUALITY of electricity. I don't think the question was what is the barest of bare minimums, but more like what should be done...and I say the maths will answer...they usually do. just because current takes the least restricted path to ground doesn't mean we should take short cuts...

the only way the utility would upgrade that pot without a power survey and cost once it has been established is if it tested bad with the blow dryer. simply stating the power is of poor quality would never be cause for a replacement, let alone an upgrade. sounds pretty neat that in Utah the lineman can just toss up newer bigger pots whenever they felt they needed to, but reality bears other fruits here in the land of nuts...

and furthermore, it sounds like you're making an argument to leave the transformer smaller than it should be, so you wouldn't exactly be the example of the lineman a guy would be looking for to help out with this one then, would you?

without putting anymore lipstick on a pig...what size of pot would you recommend for a 400 amp service?
 
This has been a fun conversation. I will talk to our estimator on Monday and see what he recommends for a 400 amp service. All I am saying is you can always upgrade a transformer and pull in new service wire if the transformer won't pack the load.
We do not test transformers with hair driers. We do test for bad neutrals or bad legs in the service wire with a tester that has multiple hair driers. We use recording volt meters.
I have tried to use a 50 kW diesel generator to provide temp power for a business with a 50 kva transformer only to have the customer shed load so that the generator doesn't trip out.
We have delt with sneaky farmers that kept adding load till their meter base melted down. They tried to get 120kw out of a 50kva transformer.
Some times the you can do everything right and the distribution circuit feeding the transformer is overloaded and you have to fight with the power company to upgrade the line.
I have given up trying to be an engineer for the power company and do what I am told. Sometimes I use the FM theory (fu&king magic).
 
I usually carry a spare can of smoke on my truck just in case.
 
next to the johnny balls and party hats?
 

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