Catering van generator earthing ??

[Mike Bradford]

Hi new here so take it easy chaps !!
A client of mine wishes to supply their catering van from a new generator they are purchasing, I believe it is single phase 7.5kW Inverter style generator with a 32 amp socket outlet. My query is about the earthing to the van.
The van has a DB inside with a 30mA RCD main switch and an earthing conductor going to an earth electrode.
What will happen at the generator end is my question, I presume it will be a floating earth system.
If there is an external earthing nut on the generator, is it as simple as installing and earth electrode to the nut?
Or do I some how have to reference one of the line outputs to earth, if so how do you do that, surely I don't take the generator apart ?
Or will the earthing nut already be connected to one of the line conductors and its just a case of staking it down as I said earlier?
Any help would great, thanks.

 

[Savdar1810]

Earthing body on generator, jump lead it to an external earth if its mobile, saves having to disconnect all the time. Equipotential bonding

 

[Savdar1810]

Earthing body on generator, jump lead it to an external earth if its mobile, saves having to disconnect all the time. Equipotential bonding

I'm guessing it's a diesel generator and will be placed outside van when running and brought back in when finished? If its a stationary generator and does not move use appropriate fixed measures to earth

 

[Deleted member 26818]

You can reference a conductor to earth simply by linking one of the conductors to a CPC at a plug and socket.
This should be done before any RCDs.
You’ll need to test the socket on the generator to determine whether the earth pin connects to the neutral pin, the frame/casing or not connected to anything.

 

[snowhead]

Can't say I've ever seen an earth spike from a generator when it's sat on tarmac in a lay-by.

Bet the Highways people won't be too happy if you stick a rod into their tarmac.

 

[chrisdungan]

Total waste of energy earthing the generator.
For the rcd to work make sure there is a neutral/earth reference at the generator upstream of any rcd. ie neutral earth link of some sort.
MAKE SURE ALL YOUR EXPOSED METAL IS BONDED TOGETHER. You may need to use that di k earth stud for that

 

[Mike Bradford]

Total waste of energy earthing the generator.
For the rcd to work make sure there is a neutral/earth reference at the generator upstream of any rcd. ie neutral earth link of some sort.
MAKE SURE ALL YOUR EXPOSED METAL IS BONDED TOGETHER. You may need to use that di k earth stud for that

Hi Chris

thanks for reply, what is "You may need to use that di k earth stud for that" please ?
Thanks Mike

 

[DPG]

I'm hoping the missing letter isn't a 'c'.

 

[chrisdungan]

haha
it can be a "c" if you wish
I actually meant dinky

 

[chrisdungan]

Remember the generator is an isolated supply. so normal mains rules don't apply.
An earth peg is a total waste of time unless you do the same for the van............. yeah right!
The key is to bond everything metal.
Just have a careful read of your local caravan and generator regs or standards.
If the genset is 3 phase bond the starpoint to the frame and the earth bar.
Single phase it's usual to bond one side to the frame. It probably actually doesn't matter which side. Nominate one leg as the neutral and bond it to the frame and earth terminal. That way your downstream RCDs have an earth reference to enable them to work.
Be careful if the generator has an RCD and the unit you plug in has an earth / neutral link. ( a common issue here in New Zealand)

The only complication with single phase deciding the phase/ neutral maybe some built in control systems.

 

[chrisdungan]

If you're curious about driven earths in these mobile/portable situations, I don't know what your UK rules are but a driven peg needs to be at least 1.8m to be even marginally effective. A single peg's resistance to earth can be really high even in soft damp soil.
in other words ..... don't bother

 

[ChipFanDave]

I think HSE information document 482/2 covers this.

 

[davesparks]

If you're curious about driven earths in these mobile/portable situations, I don't know what your UK rules are but a driven peg needs to be at least 1.8m to be even marginally effective. A single peg's resistance to earth can be really high even in soft damp soil.
in other words ..... don't bother

Assuming you mean earth electrode when you say peg then the standard 1.2m rods are effective for temporary installations. I have set up many generator supplies for events in my career and have always used 1.2m rods to achieve satisfactory resistances to earth.

UK rules will depend a little on where the van is to be used, bs7671 will always apply but other regs may also apply. For events this would be bs7909.

 

[ChipFanDave]

All the generators we have delivered come with a 1.2 rod (we never use them).I can't see the point in the hire companies supplying them if they were not much use.

 

[chrisdungan]

Davidsparks interesting differences between countries.
Our standard rod is 1.8, anything shorter is ineffective.
Here in NZ our various standards for: generators, shows and carnivals, temp power, film locations etc etc all specifically advise against driving an earth peg/rod due to the generally accepted uselessness/high resistance of a driven rod. For electrical safety here the preference is to not to rely on a ground connection but to use RCDs. The only time we have issues is when we get a "show" from overseas like the USA where the location manager insists on a rod. We just go yeah yeah and shove something in just to humour them.
Oh and I'm an old fart I've done temp power stuff for over 40 years.