Generator in steel barge

[kbs2244]

My son has just bought into a pier and dock repair and install business.
Major equipment is a big steel barge with a hydraulic crane.

On occasion he need 100 VAC for drills, saws, and such.
So he got one of those construction site generators.

My concern is grounding the thing when he is out on the water.

The generator sits on rubber feet so it may, or may not, be in connect with the steel hull of the barge.
Since the barge is in the water I am sure it is a good ground.

Should I have him run a ground wire from the generator frame to the hull or are these generators in some kind of self contained world.

 

[RPH]

Ground it to the barge. Where I work we build an induction heating system for plate straightening for large ships. It is in a self contained pod but must be grounded to the ship or arcing occurs.

 

[mrb]

this has nothing to do with 'earthing' or the ship sitting in the water. The idea is to provide a path for fault current so the protective device (breaker and / or GFCI) opens when there is a ground fault (short circuit)

Read this http://ecmweb.com/grounding/electric_grounding_vs_bonding/

Personally I think the generator should have its frame bonded to the ship steel (and there should be a N-G bond in the generator)

 

[mrb]

here is some more explanation:

Currently the NEC in Article 100 defines the terms "ground" or "grounded" as "connected to the earth or to some conducting body that serves in place of the earth." Yet, the NEC often uses the term "ground" when it really means "bond" (connected to an effective ground-fault path to clear a fault) [250.2 and 250.4(A)(5)].

Grounding - Grounding metal parts to the earth in premises wiring is only useful to provide a path for lightning, shunting high-frequency noise, or reducing static discharge.

Bonding - Bonding all metal parts together and then to the system winding (typically to the X0 terminal of a transformer) is done to provide a low-impedance path to the source (system) to facilitate the opening of the circuit-protection device to remove dangerous voltage on metal parts. In addition, bonding the system to metal parts (typically to the X0 terminal of a transformer) stabilizes the system voltage to the metal parts and it provides a zero system reference (to the metal parts).

It took me over 20 years to figure out that when the NEC, as well as books and magazine articles, state "ground or grounded" they rarely intend that the metal parts be connected to the earth or to some conducting body that serves in place of the earth. Typically, the intent is to have the metal parts "bonded" to a low-impedance path so that fault current can return to the system winding. See the definition of "effective ground-fault path" in 250.2 and review 250.4(A)(3), (4), and (5).

 

[kbs2244]

So those thing do live in their own little world.
I have wondered because I have seen them on some construction site being use with no “earth” ground anywhere near.
And I know OSHA has been there.

But it will not hurt to tie it to the barge.

Thanks for the info.

 

[mrb]

So those thing do live in their own little world.
I have wondered because I have seen them on some construction site being use with no “earth” ground anywhere near.
And I know OSHA has been there.

But it will not hurt to tie it to the barge.

Thanks for the info.

code does not require a grounding electrode (ground rod) for portable generators where the loads are supplied via receptacles located on the generator. If the generator is hard wired into a building, or hard wired into a panelboard installed on a couple 4x4s sunk in the ground for example, it would need a ground rod.

again, 'grounding' does not provide any safety. Bonding does.

 

[Mattlt]

Think of a generator on a vehicle - fire truck, ambulance, etc. No ground rod there.

 

[Tscott]

It's all about limiting touch potential. If you are running all the tools from the outlets mounted on the generator, then you could probably be OK not grounding the generators chassis to the barge. The generator chassis should be bonded together and should be equipped with its own fault interrupting devices, probably a simple circuit breaker.

If you are using the generator to power a system of outlets mounted to the barge, then those outlets should be bonded to the barge and the barge should be bonded to the chassis of the generator. This way if you have a fault and the barge becomes energized through the outlets being bonded to it then there is no touch potential between the barge and the generator or the barge and the outlets.

The only potential problem I can see with bonding the generator to the barge is that it could be possible for the barge to be at a higher potential than the dock you are pulling up to. You could run the risk of someone becoming the connection for that voltage potential to go to ground. I would say this is probably a pretty rare case as long as all bonding straps are clean and corrosion free.

Tom

 

[gjkooij]

Hi,

allways ground a rubber or flexible mounted engine. When the engine is running, it is creating a current, just by running. This current needs to be able to escape. If not, you get electrolityc damage to the engine. I have just taken away a flexible mounted engine of 3 years old. It was completely eaten away inside by this electrolisys. The engine was a write-off.

This all happened on a ship by the way. The shipyard that installed the engine 3 years ago siad it was not necceary to ground the engine. The first thing the supplier asked when there where problems was if the engine was grounded. When the answer was no they said they would find a new engine asap. There was really no need for any further inspection, they knew what it would look like inside.