Vehicle Mounted Generators

[Craig Clayton]

Gentlemen
This is followup to a posting that I made before on a polesaw that was powered by a generator. I had some members ask some very important questions that I felt needed answering. The cart that the generator is on is a vehicle and the grounding of the generator is to be bonded to the vehicle. This applies only to portable cord connected tools. I researched every technical paper that could be found. The issue starts when you talk about the 5KW range of generators which moves on to the other uses of them, which you will notice that I am not going to mention. The issue to correct my generator was that it needed to be bolted to the vehicle and all non current carrying metal parts to be bonded to the vehicle. You will notice a green wire in one of the pictures. I made a cover to carry my cords in so that they could be kept with the generator. I took apart the setup in stages to show what could be done with it. The generator can be unbolted and loaded in a truck for transport very easily. I found American rules that state that the size of the generator is not important provided that it is vehicle mounted and has cord connected tools.On Google I typed in ( Vehicle mounted generators ) and came up with 10 PDF files. The slippery slope is when the generator is not mounted on a vehicle with cord connected tools , then a large number of other rules come into play. I read all 30 of the other files that I could find. I also found that manufactures throw in their manuals to ground the generator just to cover themselves. That brings in other problems as to people running around driving in ground rods at random. I am a electrician and have studied this beyond what I have typed so far. If there are any questions I can post up the files where I found the information.
So bolt your generators down and bond to the vehicle.
Craig Clayton

 

[hr3]

I'm not disagreeing with what you have done,,or stated but don't you think that 釘olting and bonding are the same thing.. ??? If the generator is already bolted to the metal frame the the ground wire would be a redundant ground,,

 

[Kubota-guy1911]

Is your neutral bonded to ground?

kj

 

[CharlieS]

Retired master electrician and building inspector here, & Craig brings up some good points. To expand a little, unless local codes are more stringent, NEC must be met.
Per Article 250.34 a portable generator can be set upon the ground without further grounding other than all gen. frame parts must be bonded.

While not specificly mentioned wagon mounted would be considered vehicle mounted and all metal parts would need bonding to the generator frame, in this case however should have a grounding attachement to either a cold water supply or ground rod, via no less than #6 copper wire.
Neutrals and grounds are not to be bonded, Article 250.36(B)
Article 445 also contains other generator requirements.

 

[Craig Clayton]

To hr3
I am a Canadian electrician and I follow the Ontario electrical code. It is the same as your NEC, except the rules are in a different number order. Back to your bolting, the technical articles about vehicle mounted generators are all American. We just copy alot, so the American welding society states that the generator must be BOLTED to the vehicle. As the AWS refers to the NEC they want all non current carrying metal parts to be BONDED to the vehicle. So first you bolt it down mechanically, because some times there are rubber pads or cushions that do not Bond the metal. The second part is the Bonding wire that jumps the gap around the possible rubber pads.
In doing research I found a current maker of generators with a picture of their generator running in the back of a pickup truck with a plastic bed liner and a very happy person drilling holes or such in the field. So there is alot of wrong installations going on.
I did not write the rules, I just try to follow them.
Craig Clayton

 

[Craig Clayton]

To Kubota-guy1911
This is the start of the slippery slope on the 5KW generator issue. The articles that I could find about this all state that the generator must be kept in proper order and tools and cords must be top notch. When the generator is mounted on a Vehicle I could find no reference to a floating or bonded neutral type when cord connected tools are used. My generator has a floating neutral. A vehicle maybe sitting on rubber tires axle deep in mud or a float trailer may have the 10,000 pound landing legs down, so the grounding issue is unknown. The reason the regs do not talk about ( grounding ) because that is another subject and you could set your self up for a electric shock if you ground a vehicle and things go wrong with tools or cords or short circuits. The slippery slope is how the little generator gets pushed from on the ground ,to vehicle mounted, to construction useage , to standby installation , and even on sail boats ( where do you drive in a ground rod there).
Craig Clayton