MEP Power Distribution

[lonesouth]

is there any particular wire I should be using for this? I've got a bunch of 12/2 romex I was figuring on using, but thinking better of it after discussing NEMA codes in the other thread.

 

[DieselAddict]

You can run 12/2 ROMEX for a 20a 120v or a 240v circuit (no neutral). You would put black phasing tape on the neutral for the 240v circuit but it is OK to do it in this situation where in the other situation (changing a load carrying conductor to a neutral) it isn't OK. You can't run ROMEX exposed to the weather though. If it runs outside you need to put in in conduit.

 

[lonesouth]

Do the NEMA codes even apply to a mobile generator? All of this will be mounted on a trailer.

 

[DieselAddict]

NEMA is an equipment standard. It covers enclosures and stuff like that which includes items where power carrying components are contained.

NEC is what we refer to as the electrical code. If the question whether electrical code applies to mobile generators the answer is yes, it does.

AND it gets a bit tricky depending on what you are going to use the generator for (what it is connected to).

Examples:

1. If you connect a mobile generator to an existing structure with its own ground and ground/neutral bonding then the generator can't have it bonding jumper installed nor does it REQUIRE its own ground rod.
2. If you take the SAME generator and put it in the middle of a field to power a pump (not mounted on the generator vehicle) for irrigation or livestock you would be required to drive a ground rod and connect the bonding jumper. This does assume that the pump doesn't also have utility power available. If you have utility power then it would be the same as #1 since the neutral would be bonded as part of their connection.
3. If you use the SAME generator to power cord connected equipment you don't have to drive a ground rod but you do have to connect the bonding jumper AND the generator has to be bonded to the frame of the vehicle (trailer or truck).

So things with generators can be complicated and confusing.