Re: GROUNDING TRAILERS IN MOBILE HOME PARK
By Allen: the sub panel that feeds each site must have an isolated ungrounded conductor the same as in any sub panel.Correct ?
Were not talking about RV's but manufactured homes.
A 2-pole 3-wire 30 amp receptacle on a 120/240 volt 3-wire service would be a violation if it fed the trailer directly. One the code requires a minimum of 50 amps unless it meets the exception 1 to 550.10(A) which would allow a 40 amp, but in no case is a 3-wire cord or receptacle allowed, even if it is an RV. (unless it is a 120 volt only circuit)
Allen not the feeders to the disconnect(sub panel?) but the feeders from the disconnect (sub panel) to the trailer.
It does not matter if it is cord and plugged connected (Life Line) or permanently connected by feeders in conduit, it has always been required to provide a 4-wire connection to the panel inside of the trailer, and the EGC has to be insulated. The exception to 550.33(A) only allows a 3 wire connection if there is a disconnect between the service equipment and the trailer, this 3-wire connection has to end at the disconnect and then it is required to have 4-wire into the trailer that includes an insulated EGC.
Read 550.33(A)
550.33 Feeder.
(A) Feeder Conductors. Feeder conductors shall consist of either a listed cord, factory installed in accordance with 550.10(B), or a permanently installed feeder consisting of four, insulated, color-coded conductors that shall be identified by the factory or field marking of the conductors in compliance with 310.12. Equipment grounding conductors shall not be identified by stripping the insulation.
Exception: Where a feeder is installed between service equipment and a disconnecting means as covered in 550.32(A), it shall be permitted to omit the equipment grounding conductor where the grounded circuit conductor is grounded at the disconnecting means as required in 250.32(B).
What I was pointing out is the exception would allow him to install a disconnect at the trailer, and keep the 3-wire feed then change over to a 4-wire.
This disconnect has to be service rated, shall be located adjacent to the mobile home and not mounted in or on the mobile home. 550.32(A) be mounted at least 2' above grade, 550.32(F) in sight from and no farther then 30' from the trailer. 550.32(A)