SImple trailer wiring questions

Stupid question - the green wire in the bottom right corner - this is the ground running from the box to the frame, right?

 

Correct.

 

Excellent - this thread is going to come in handy in the future.

 

Just curious, why did you connect it like that (under a mount screw) rather than to the ground bus at the top of the panel?

 

Because it was easy and someone recommended grounding the box to the frame. As I said in the original post I am no electrician.

 

You do want the electrical ground of the power drop tied to the trailer chassis. In fact, NEC requires it.
Without that bond, GFIs may not protect you.

I was just wondering why he chose to ground it that way rather than to the bus bar designed for grounding. The connection method he used (under a mounting screw) may become loose over time, resulting in less/no protection. A connection to the ground bar doesn't require that the mounting screw remain tight, nor that the paint on the box be chipped to provide a good, low impedance connection to the electrical ground.

 

The problem was neutral tied to ground. That is a violation and a problem, and most assuredly was the cause of your tingles.

In houses, the power system is grounded at the service entrance. If the house has a metal frame, it is also grounded, per code. Why would a mobile installation be any different? When done properly, the ground is not a current carrying conductor, but rather a safety bleed of stray voltage.

If the chassis is not tied to the electrical ground (not neutral, the GROUND), then any 120V hot conductor contacting the chassis will make the entire chassis hot, and give you a huge potential for shock, up to and including lethal shock. With the chassis tied to ground, if a 120V hot conductor contacts the chassis, the breaker or GFI will trip, providing protection.

Neutral and Ground should never be tied together in any vehicle installation.
In buildings Ground is tied to Neutral at the service entrance, mostly for lightning protection. After that one bonding point, they should never be interconnected ever again, including runs to outbuildings.

 

This is exactly what I am describing. We are in agreement. If the AC power ground is NOT connected to the chassis, you will be subject to shock from a bad/frayed/miswired cord. This is prevented by bonding the chassis to the AC ground, providing solid return path back to the electrical ground instead of through you.

The NEC treats these kinds of installations much like RV power or temporary power in tents. Both require bonding the metal parts of the enclosure to the electrical ground.

 

Bump.
I just got a small 6x10 to haul to the track. I have an 7000 watt genny I want to bring to power the trailer and pit. I want to basically copy what Dobr24 did for lights, outlets etc.

Is this the right type of box to use?
https://www.amazon.com/Square-Schne...1543430020&sr=8-2&keywords=30+amp+load+center

The generator has a 30A 120/240V outlet. If i understand this correctly, I can feed this box with that 30A plug and then split off circuits for AC, lights, and interior/exterior outlets. Is that correct? I could also plug into a power pole at tracks that have those?
If its wired like Dobr did his is it pulling 240 or 120 to the box? I would guess its 1 line its 120.

If i wanted to get the most amps from my genny should i run 240V (2 legs) into the box and then split it into 120V? How would that look?

Thanks guys.

 

There is an 8/16 version of that that is just a few $ more, and the same overall size. The difference is space for two more breakers. The one Dobr put in is the 6/12 version, and you can see spaces for the two extra breakers (one on each end of the 6 he has mounted in the pic), but in the 6/12 version, there is no electrical supply tab in those spaces.

If you have the space for it I'd go with the outdoor version which has a metal door to protect the breakers from stuff banging around in the trailer, but make sure you have clearances to open the door if you choose that option.

If you have a 120/240V supply ( a 4-pin connector) on the generator, you can wire it up as a 240V system, and use single-pole (120V breakers for things that need 120V) and a double-pole breaker for those things that need 240V) If you wire it for 120/240V, do NOT jumper the two input lugs together.

 

Thanks for the input. Ill look for the 8/16 box.
Yes the Genny has a 4pin (14L-30 I think) outlet.
If i wire it like you said, i would run one leg to each set of lugs, correct? Would i bebable to add a main breaker to the box like Dobr put in? Or would i need a different box? Double pole breaker?
I can wire in new outlets, ceiling fans, etc but starting from scratch on this stuff is where im lost.

Thanks again...

 

If you wire it from the 30A 120/240 plug on the genny, then you can use a 2-pole 30A breaker as a main breaker (it takes 2 slots, so another reason to look for the 8/16). The Red and Black (hot lines) would go to the 30A 2-pole breaker, the White goes to the neutral bar, and the grounds go to the ground bar (you have to buy that separately and install it in the box if you are using the Square D stuff).

Once you have the main feed connected, then you add breakers/wiring to the lights, outlets, A/C, etc. as necessary. Use GFCI outlets, or alternately, GFI breakers.

You can get adapters to use this 30A 120/240 plug with RV 50A 120/240 connections at tracks, or a special cord could be made up to use the 120V 30A RV plug as well (no 240V appliances will work on the 120V plug-in).