Single phase installation off a three phase cutout and distributors fuse details??

[Guest112]

Hi guys,

Just finished a job installing communal lighting and power in 7 blocks of flats,

The supply for each building is the same a TNS 3 phase cutout with a feed jumped off one of the phases to the meter and from the meter supplying our single phase CU, the flats are then jumped off various phases but that's nothing to do with us we only came from the meter to supply our new CU

sooooo on page 2 in the supply characteristics in the first colum I have ticked the TNS option

then the number and type of wiring conductors I have ticked 3 phase 4 wire

then the nature of supply parameters iI have entered 400 and 230 as nominal voltages 50Hz frequency then my Ka and Ze obtained and then 1 source entered

then the characteristics of primary supply overcurrent protective device I have entered U through all the boxes as I can not determine the size and type of protective device and there isn't any information displayed on the fuse carriers,

Is this correct? my boss sent me up to check the cutouts for more information but I am not authorised to pull the distributors fuses to check so surely a U for Undetermined is satisfactory for the NIC forms??

any help would be greatly appreciated

Thanks

 

[Guest112]

Re: Single phase installation off a three phase cutout and distributors fuse details?

anyone??

 

[timbobelfast]

Re: Single phase installation off a three phase cutout and distributors fuse details?

Can you not obtain through enquiry to the DNO??

 

[Richard Burns]

Re: Single phase installation off a three phase cutout and distributors fuse details?

The nominal voltage to earth Uo will be 230V in all cases. It would only be 400V for phase to phase voltage, U, but I think NICIEC do put both on there.
If there is no information given on the DNO service head for the size of fuse then I would normally write N/V (not verified), but unconfirmed I suppose if that is what NICEIC want. Then this would sound to be all you can do unless you want to follow timbobelfast's advice, which is the approved answer, but may take more time than you expect to be unable to get a response!

 

[Guest112]

Re: Single phase installation off a three phase cutout and distributors fuse details?

Can you not obtain through enquiry to the DNO??

That was the suggestion I was going to put forward to my boss but surely U is an acceptable practice on the forms as this is a very common problem with testing???

 

[Guest112]

Re: Single phase installation off a three phase cutout and distributors fuse details?

The nominal voltage to earth Uo will be 230V in all cases. It would only be 400V for phase to phase voltage, U, but I think NICIEC do put both on there.
If there is no information given on the DNO service head for the size of fuse then I would normally write N/V (not verified), but unconfirmed I suppose if that is what NICEIC want. Then this would sound to be all you can do unless you want to follow timbobelfast's advice, which is the approved answer, but may take more time than you expect to be unable to get a response!

cheers mate, yes I'm going to suggest to my boss regarding contacting the DNO but for now I have filled in the sections with a U and he can do what he wants regarding obtaining the information, perhaps he will speak to the customer and see if they would need the information or not?