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Originally Posted by RJ82much
Sorry Timothy, but Bob Thompson, master electrician did not fully understand your application. You do have 100 amps total, available for use, at 120 volts, in your motor home.
The way to look at it is thru power analysis. For the techies in our group, I'm ignoring some details, like power factor, etc -go easy on me.
Bob Thompson is correct about the 50 amps at 240 volts. The power of that service is (240 volts) times (50 amps) = 12,000 watts. You have 12,000 watts available to use in any form you wish.
If you're only using it at 120 volt level, then you calculate
(12,000 watts) divided by (120volts) = 100 amps.
OR, suppose you have a really cheap welder. If you set it on a 12 volt AC tap, you will have
(12,000 watts) divided by (12 volts-ac) = 1000 amps-ac !
Please, think of everything in terms of POWER = volts x current which is the same as:
amps = POWER / volts
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Bobs response to this below.
Answer 50 amps at 240 volts is indeed 12,000 watts, and it's 12,000 watts spread equally (hopefully) across two legs (A & B) of a normal 240/120 volt single phase service. Each leg (A or B) will "see" half (again, if the loads are equally distributed) of the available power, or 6,000 watts. And 6,000 watts divided by 120 volts is indeed 50 amps, and if you add A & B, you'll get 100 amps, theorhetically, but two problems....one, your 50 amp service WIRE is not designed for 100 amps; and two, if for some reason you had all 120 volts loads, and placed them all on a single phase wire, you'd be overloading one of the service wires, generating a lot of heat, possibly start a fire and your service would fail. This is the practical world and why we "balance" services, but your friend is right in one respect....12000 watts is 12000 watts.
Bob Thompson
Master Electrician
Previous business owner.
And to sum this up, in a perfect situation the neutral would carry no current if the load is balanced, that is why you only need one neutral it only carries the unbalanced load.
This is the end of the argument for me, we are both right/wrong in a sense.