Pure sine wave generator temporary install

[Joe S]

I have been asked to Supply & Fit a Pure Sine Wave Generator to a solicitors office for 1-2 days while the main gets switched off in the road for a building development alteration. They have been told by their IT guy it has to be a certain kind of generator due to the computers.

The Install is a 100a TNCS supply a. Henley Block which then supplies 4 other smaller boards. The total demand of all of the boards is 64.8A combined. Obviously they can run a Skelton type operation for a day or two to keep the load usage to a minimum.

I was thinking of installing an Ip rated enclosure with a 40a rcd and earth rod outside by the generator and then running a sub main to the Henley block. I was also going to put the mains tails into their own Henley block for the duration of the works so as not to have two supplies running together if they turn the power back on early.

Does this sound the right thing to do as I've never had to install a temp generator before? Also, where is the best place to hire them as I can't seem to find one at least 6kva?

Thanks in advance.

 

[jeremy]

"Obviously they can run a Skelton type operation for a day or two to keep the load usage to a minimum."
Does Damien know about this?

 

[Knobhead]

And what stops back feeds in to the incoming supply? Both Ph&N need to be disconnected at a centre off change over switch.

 

[Engineer54]

There are loads of Generator hire companies, whether you have one near you i wouldn't know, but i'm sure there used to be one down that way in Kent.

You'll be hard pushed to find a gen-set suitable for IT of that low rating, far more likely to be over 10 KVA. And yes, you will need a temporary earth rod, as you could well be losing your main earth as well as power... Give the gen hire company full details of your requirements (IT load etc) and they will be able to provide a generator suitable for your purposes, and will even provide you an installation guide for your requirements etc

Install a suitably sized switch fuse isolator, via henley's and use the existing CU/DB RCD's. Just make sure that if DNO supply does return unannounced, it stays at the service head.

 

[Knobhead]

Never mind loosing the DNO earth, the earths have to be separated. It sounds like the DNO are working on the cables so there’s a danger of exporting a fault and injuring cable jointers.
You need to contact the DNO and as well the hire company.

 

[Engineer54]

It's probably the DNO that have advised these businesses they need to make alternative arrangements. Normally they would be providing the temporary generator supply, ...it's normally the case anyway, if the disruption of power is for the suppliers benefit or for fault repair over an extended period (8 hours).

Anyway as far as the earthing is concerned, only the incoming main earth (TN-S/TNC-S/PME) needs to be removed/disconnected and isolated from the MET, and replaced by the temporary rodded earth.

 

[Joe S]

And what stops back feeds in to the incoming supply? Both Ph&N need to be disconnected at a centre off change over switch.

This would be taken care of with a separate Henley to keep the mains tails away from the installation and generator.

I shall check with the solicitors about the supplier providing temp power.

 

[GLENNSPARK]

I have been asked to Supply & Fit a Pure Sine Wave Generator to a solicitors office for 1-2 days while the main gets switched off in the road for a building development alteration. They have been told by their IT guy it has to be a certain kind of generator due to the computers.

The Install is a 100a TNCS supply a. Henley Block which then supplies 4 other smaller boards. The total demand of all of the boards is 64.8A combined. Obviously they can run a Skelton type operation for a day or two to keep the load usage to a minimum.

I was thinking of installing an Ip rated enclosure with a 40a rcd and earth rod outside by the generator and then running a sub main to the Henley block. I was also going to put the mains tails into their own Henley block for the duration of the works so as not to have two supplies running together if they turn the power back on early.

Does this sound the right thing to do as I've never had to install a temp generator before? Also, where is the best place to hire them as I can't seem to find one at least 6kva?

Thanks in advance.

so this means no scams & partP5WWkevs then....