Small Generator Earth Question

[rolyberkin]

I have a friend who has just bought a horse box with a pizza oven in it. He would like to use a small generator with it to power two fridges and no doubt a couple of lights.

The load would be no more than 1kw total so I have had a look at the little Honda and Yamaha suitcase 2kw units which I think would be fine. I understand there are machines where an earth can be supplied to the chassis via the neutral and others where the earth is floating.

I have read the HSE guidance and Sec 717 and am still a tad confused re whether a local earth rod would be required in certain circumstances (i.e on a field) , I understand that some event organisers stipulate this as a requirement. What if the unit is stood on a car park and an earth rod is not possible, do the generators have a connection which can be used?

I have considered the use of a small 30ma RCD protected plastic consumer unit and the use of braided SY cable for connections to prevent damage and to provide ADS.

I forsee a solution will be required which allows him to plug in the supply where one is locally provided and then use his little generator when not is there anything I need to be aware of or does anyone do these type of installations that could advise me of pitfalls or a good small generator @davesparks ?

Thanks

 

[Leesparkykent]

Two leads. One for plugging in to the mains when its available and the other lead with a neutral earth-link for plugging in to the generator but then you would also need a spike.

 

[rolyberkin]

Thanks Lee, if he is on a car park and there is no no ground for an earth spike what happens then? I see a lot if these catering set ups on our High Street when they have farmers markets?

 

[Dan]

I went camping a few months ago and a guy came round with one of those types of pizza ovens in a trailer type thing. Not sure how his electrics were powered though.

 

[davesparks]

I have a friend who has just bought a horse box with a pizza oven in it. He would like to use a small generator with it to power two fridges and no doubt a couple of lights.

The load would be no more than 1kw total so I have had a look at the little Honda and Yamaha suitcase 2kw units which I think would be fine. I understand there are machines where an earth can be supplied to the chassis via the neutral and others where the earth is floating.

I have read the HSE guidance and Sec 717 and am still a tad confused re whether a local earth rod would be required in certain circumstances (i.e on a field) , I understand that some event organisers stipulate this as a requirement. What if the unit is stood on a car park and an earth rod is not possible, do the generators have a connection which can be used?

I have considered the use of a small 30ma RCD protected plastic consumer unit and the use of braided SY cable for connections to prevent damage and to provide ADS.

I forsee a solution will be required which allows him to plug in the supply where one is locally provided and then use his little generator when not is there anything I need to be aware of or does anyone do these type of installations that could advise me of pitfalls or a good small generator @davesparks ?

Thanks

Sorry for the slow reply, I've been away from the forum for a while.

The first thing I'll say is don't use SY, it ain't suitable for outdoor use and is specifically prohibited in BS7909 iirc. H07-RNF flexible cable (tough rubber sheathed) is the stuff favoured by 7909 and is the best option.

A simple system is defined in 7909 as one below 6kVA and is permitted to use a generator with a floating earth as what will essentially be an electrically separate system, subject to everything connected to it being all good and safe. Although I'll have to check up on this to be certain as the systems I work with are always somewhat bigger than 6kVA.

The problem with events is that there are a lot of people in positions of authority without a clue about what they are looking at, yet will argue till they are blue in the face that they do. Things are very slowly improving as bs7909 becomes better known about and councils are starting to recognise some of the common issues. For example it I shall becoming more common for SY cable and blue arctic cable to not be allowed at events, but there is still a long way to go.