Workshop Supply

[willy fixit]

Hi Guys (and girls),
Can anyone come up with a reason not to fit a 2 way consumer unit into an outside meter box to supply a workshop extension?

 

[driverman]

Reminds me of a job that i went to when working for a DNO. 3 phase flush OMB was installed in a stone wall as per spec in readiness for the DNO 3 phase u/g cable to go into. Got on site,opened the 3 phase door only to discover a 3 phase metal clad switch fuse in there! It completely filled up the box! God knows what the electrician was thinking off. Needless to say....he had to remove it.

 

[Engineer54]

Isolator one thing, as we know makes life easier to isolate the supply 100%. Switch fuse in there I'm not so sure.

A switch fuse to protect extended tails is more for their benefit than the customers installation. I've not heard of a DNO not allowing a switch fuse to be mounted in an external cut-out cabinet!!

 

[andyelectric]

You only need ONE switch fuse, and as far as i'm aware, these can be fitted into DNO cut-out/ meter cabinets. The buggers should be fitting DP isolators as standard/matter of course anyway!! All this crap about too expensive, ....what's the standing charge for, if not for supply maintenance and improvement work...

This was a 3 phase move for 3 flats with one flat having economy seven and 2 meters/supplies. As I have already stated, SEPD were happy with customer gear inside the enclosure, but not on their boards. The installation literature provided was also clear about this. The switchfuses were fitted in lieu of the double pole isolators.

So in fact switchfuses were required

 

[Engineer54]

This was a 3 phase move for 3 flats with one flat having economy seven and 2 meters/supplies. As I have already stated, SEPD were happy with customer gear inside the enclosure, but not on their boards. The installation literature provided was also clear about this. The switchfuses were fitted in lieu of the double pole isolators.

So in fact switchfuses were required

That's fine if the cabinet/enclosure is of sufficient size to accommodate the extra devices. I'm just trying to think of a typical Cabinet/enclosure where it would all fit in, not using the back fixing boards that usually take up the whole rear of these enclosures... must be a bloody big cabinet to contain a 3 phase cut out and all those meters and switch fuses etc!! Got a photo??

 

[andyelectric]

That's fine if the cabinet/enclosure is of sufficient size to accommodate the extra devices. I'm just trying to think of a typical Cabinet/enclosure where it would all fit in, not using the back fixing boards that usually take up the whole rear of these enclosures... must be a bloody big cabinet to contain a 3 phase cut out and all those meters and switch fuses etc!! Got a photo??

You are correct, the enclosure is a large IP55 metal 1m x 1m box, although the dno were happy for me to 'build' my own enclosure if necessary. A standard plastic outdoor enclosure would typically only contain one board(the DNO's) and any switchfuses would have to be mounted internally within the DNO's 3m tails limit, ensuring the tails do not run through the cavity.

This is why I have suggested that it is likely the OP will have to mount his CU internally unless he has an overlarge meter cabinet large enough to contain his own board.


I'll have a look see if I can get a photo up, as I have another thread running about conversion to a tncs head for the installation.

 

[driverman]

DNO I worked for would never allow 3rd party equipment on their board. However when taken over by another DNO it was allowed. New DNO would allow those 60amp MEM switch fuses which were compact to be fitted usually top right hand corner.

 

[andyelectric]

That's fine if the cabinet/enclosure is of sufficient size to accommodate the extra devices. I'm just trying to think of a typical Cabinet/enclosure where it would all fit in, not using the back fixing boards that usually take up the whole rear of these enclosures... must be a bloody big cabinet to contain a 3 phase cut out and all those meters and switch fuses etc!! Got a photo??

Been trying to upload a photo but cannot for the life of me work it out!!!!!!!!!!!

 

[richy3333]

That would kinda defeat the whole point of having a switch fuse if the tails are over 3 metres. If that was the case i'd be having a few words with the DNO's Area Engineer, rather than listening to the meter installer.

I concur. My switch fuses nearly always go next to the cut-out

 

[driverman]

Are you not meant to have 1 point of isolation? If con-unit indoors, then 2 way unit fitted in OMB that creates 2 x isolation points. I know done like that years ago with several con unit/ sw/fuses installed by the meter position.

 

[willy fixit]

Are you not meant to have 1 point of isolation? If con-unit indoors, then 2 way unit fitted in OMB that creates 2 x isolation points. I know done like that years ago with several con unit/ sw/fuses installed by the meter position.

Good point DMan is it not the same as splitting the tails inside to add a shower unit or the like?

 

[7029 dave]

A switch fuse to protect extended tails is more for their benefit than the customers installation. I've not heard of a DNO not allowing a switch fuse to be mounted in an external cut-out cabinet!!

The sunny boys have cramped all their equipment inbox, meter an all. lol