One for the sparkies please...

Oly

Well-Known Member
We're having SPEN bring 18KVa 80A supply under the lane into the hedge on our site for domestic usage. We are having to provide a cabinet for SPEN to house their meter board nestled into the hedge. From this meter board we will then get our sparky (yet to be commissioned) to run a cable underground to serve a consumer unit indoors.

My question is; What will be (roughly) the physical size of the isolator switch that will be required to also be within the meter cabinet?

Presumably we will need something akin to one of these? Isolators Switch Fuses - QVS Electrical Supplies | Electrical Wholesaler

Obviously we will later be employing a sparky for all the works beyond the meter, but all I need for the moment is the physical size of the right type of switch as per the link. From this information we can then build the cabinet big enough to not only house SPEN's gear and the meter, but also our isolating switch.

Many thanks,
Oly
 
Allow plenty or room and get a decent quality enclosure to save messing about in the future. There's nothing worse that leaking enclosures that don't shut properly.
 
Not sure what the Authority are asking for but for a domestic supply the authority's meter should also come with an isolator to which your sparky can connect. They may require you to isolate your supple if its more than 3m from their meter point.

If you allow about 300mm square and get a two pole 80A isolator.(assuming its a single phase supply)
 
We're building a brick free standing cabinet on a concrete base, hence the question.

The supply is single phase and the meter will be more than 3m from the building. Any idea if any on the link would be something like what our sparky would install?

Some good info there so far, many thanks.
Oly
 
Not sure what the Authority are asking for but for a domestic supply the authority's meter should also come with an isolator to which your sparky can connect. They may require you to isolate your supple if its more than 3m from their meter point.

If you allow about 300mm square and get a two pole 80A isolator.(assuming its a single phase supply)

spot on for Hydro/SSE but also allow for isolator big enough to terminate a 25mm 2 or 3 core armour cable as you can get physically small isolators but they are not suitable for terminating an armour into which is the cable type I would assume you are running to house but there are plenty suitable ones within the 300mm square dimension quoted previously I would just go into a local electrical wholesalers and they should produce you a choice off the shelf
 
Do you know the type of earth system. If its "TT" you will need a 100mA rcd to protect your installation. I'd put in an 80/100A mcb (rcbo if its a tt system) then your unlikely to take out the REC fuse in the cut out. You might find they object to you mounting your own equipment on the meter board. Best to talk to them and see what they say, they are all different. i'd get a price from them to install the mcb/rcbo if they are prepared to, save a lot of buggering about and attendances etc.
 
Being a new supply I'd get the 3 phase supply laid in as far as you can. Then split it out to three separate single phases. All professionally done within regulations of course.
That way you can be most flexible in the future, & if you ever need 3 phase it'll be MUCH cheaper.

Ian
 
SPEN specify that their board is a minimum of 450mm above ground level due to generic flood risk reasons. However, this is no where near any flood risk, and the ground to the rea being over a metre lower. As such, could I locate my isolating switch below their board (still ~150mm above ground level)?
 
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