2oo AMP service with existing 125AMP Panel

Speedy Petey · 04-28-2012, 08:25 PM

Quote:

Originally Posted by TomGourdin

My original question was how to properly connect two service panels to a new underground feed, not why it was needed (or not). Since this is a DIY forum, I understand your reluctance to help, but why critisize what you don't know the details of?

Which is why I asked what the details were. Many people like to leave out details when it benefits them, such as this case.
I am in no position to, nor do I choose to, help anyone in a situation like yours. This is a job for a professional, period. I am sure others don't care, but I do, which is why I make choices such as this.

DIY stands for "Do it yourself"...FOR YOURSELF.

Good luck to you, and good luck to your bosses and the campers as well.

andrew79 · 04-28-2012, 09:44 PM

Not that i begrudge anyone capable of doing their own work but i'm curious as to how it works in the U.S. Here a place such as that would have to get a permit to do the work. If the utility is required to come and disconnect anything a permit has to be issued with a person/company with a masters license and a contractors license(with insurance). Now a homeowner can do their own work but the inspectors grill them to make sure they didn't just say they did it and hire it out. If the utility isn't required they could in theory do the work without a permit but if something ever happened and their insurance found out any claims would be null and void at that point. If you all don't want to clutter up the thread please PM if you know the rules for this cross border.

In my opinion if the rules are similar all talk of competency aside it's just not worth the legal risk involved.

jbfan · 04-28-2012, 09:50 PM

Andrew, that depends on the area you live in.
Each state makes its own rules about being licensed and insured.

Where I live, you have to have a license to contract work, but not to work as an electrician.

itsnotrequired · 04-28-2012, 10:02 PM

Quote:

Originally Posted by electures

The sum of the branch circuit breaker ampacities has nothing to do with the size of the service. Service size is based on the calculated load. The calculated load is done using demand factors. Demand factors are a result of decades of data the Poco's monitor from millions of all types of homes. I order to properly help you, we need the nameplate ratings of a the appliances fastened in place plus the square footage of the building.

To give you an example, a 12 KW (12,000 watt) range has a demand factor of 8KW. So even though the range has a nameplate rating of 50 amps, only 33 amps is used for sizing the service. The online calculators take all this into consideration. Or you can try to do it the way we professional electricians do it. With a calculator, pencil and a code book.

Good luck!

what this guy said. lots of demand factor rules in the code. say this kitchen had four 12 kw ranges. total for all four ranges is only 17 kw from a service sizing standpoint. idea is that what is the likelihood that all four ranges in a residential kitchen would be running at the same time. now if we are talking about electric clothes dryers, the rules are different. load for these is 5 kw or the nameplate, whichever is greater. demand factor is 100% for the first four clothes dryers. another example is lighting. load is calculated at 3 VA per square foot for dwelling units but only the first 3000 sq ft gets a demand factor of 100%. up to the next 120,000 sq ft, demand factor is only 35% for lighting. lots of rules here.

note that these demand factor rules discussed here are for sizing services. for the individual loads, conductor size and OPD size is dictated by the equipment regardless of demand factor. using this 12 kw range example, an 8 kw maximum demand doesn't mean you can size your breaker and branch circuit conductor for 8 kw.