Temporary Power from Generator on an out building?

[Liamsparks]

Hi Guys,

I've got a question which I think the answer would be "Yes its ok" but I'm just after a second opinion and think some of you folks might have had experience with this type of set up (I haven't).

I've just wired a new out building which is going to be used as a sort of after school / weekend forest school. The building is situated in a middle of a field quite isolated from any other propertys for an "easy tap on". The installation only contains a lighting circuit,ring main circuit & Fire alarm panel so is only designed to be operated as a single phase system. The customer who owns the land isn't currently in a position for the supplying sub-main cable to be dug in across the field to the primary supply from a local barn with the adequate supply source.

My question is, is it OK / acceptable to temporarily run the building from a generator and carry out the necessary EIC from the readings from the Genny + earth stake to please building control? I cant see what their problem could be as long as all test results are acceptable and earth testing in accordance to TT values etc. Obviously the installation isn't applicable to part P not that this changes anything.

Another problem is i'm not going to be able to turn on/commission the fire alarm system because of the regular energise/disconnection will no doubt upset the system and i'm also hoping the emergency lighting batteries hold out!

Hopefully the above isn't too confusing and someone will be able to shed some light.

Thanks.

 

[Lucien Nunes]

and earth testing in accordance to TT values etc

Surely it won't be a TT system when the generator is connected?
Is it ever supposed to be run from a generator when in use, or will the mains arrive before then? If not, how will the values from the generator supply in any way represent the values to be obtained on the mains?

 

[Wilko]

Hi - yes my thought was gen-set wired as if 'mini DNO' with earth stake etc and shed as TNS? Cheers, David.

 

[Liamsparks]

Hi - yes my thought was gen-set wired as if 'mini DNO' with earth stake etc and shed as TNS? Cheers, David.

Think this is what a I meant but have gone about wording it incorrectly.

 

[Liamsparks]

Surely it won't be a TT system when the generator is connected?
Is it ever supposed to be run from a generator when in use, or will the mains arrive before then? If not, how will the values from the generator supply in any way represent the values to be obtained on the mains?

I'm wondering if the installation can be ran via Generator before the main supply can be connected as i'm unsure when this will be available at the moment.

i.e - to be running off genny temp and then when the mains supply is available to completely remove the genny set up etc.

So we're singing from the same hymm sheet can you advise how this can be adequately done?

 

[Carl S]

Only if the generator is end tapped neutral. A site generator won’t be suitable for a system wired for phase and neutral.

 

[Lucien Nunes]

Well if the installation is going to be used from the genny, then presumably this will have been designed in and the necessary earth reference considered and OCPD co-ordinated with the likely PFC on the genny etc. Therefore it should be straightforward to test as designed. If it's not supposed to be used that way, I can't see much point taking a genny along for testing other than to see the lights light up. A set of live tests will still be needed once the mains connection is completed as the characteristics will be completely different.

 

[westward10]

I think he is asking can he test the circuits with the genny supply to prove it's safety until the DNO supply is put in place, he can then retest once a permanent supply is in place. I think a risk assessment is required with regards to not connecting the fire alarm but if it is a conventional system it won't harm it being turned on and off, just replace the batteries when the permanent supply is in place. As for the emergency lighting it will probably not do them much good.

 

[UKMeterman]

Thinking about it could some of the loads be supported at 24V dc, minimal lighting and so on, and charge the batteries using solar and wind?

 

[plugsandsparks]

If this place is to be used on a genny, then what immediately springs to mind is how long it takes to charge the batteries for the fire and em lighting , it can take many hrs to charge them. It may be better to have torches and air powered hooters until a perm supply is in place