three phase switch fuse location

[jbsparks]

I am after some advice/help. Im currently on a new build home which has a new 3 phase supply put in by uk power networks. The consumer unit is well in excess of 3 meters away from the meter but the problem I have is that it is an external meter box and I cant put the switch fuse back to back. The designer of the installations has specified the switch fuse go in the meter box, they have obviously not seen the size of a 3 phase switch fuse. I can locate the switch fuse in a cupboard that is 3 to 4 meters away (that's tail length away) providing its run in the floor.

can the switch fuse be located up to 3 meters away from the meter or does it have to be located back to back/ next to meter location. Single phase switch fuses are easy to hide, box in but 3 phase are on another scale. being a million pound plus property everything has to be easy on the eye.

 

[telectrix]

chuck it back at the designer. it's his cock-up that he's not allowed a big enough EMB to accomodate the 3 phase switch/fuse. the point of the switch/fuse is to protect the DNO fuse from a fault on the tails. pointless fitting it downstream. pass the buck.

 

[Rockingit]

Are you SURE you can't fit a 4p breaker in an enclosure inside the cabinet? Or...fit a bigger cabinet.

 

[davesparks]

Ask the designer for the make and model number of the switchfuse they had in mind when they specified this.

The max length of tails before the switchgear is ultimately up to the DNO to decide, but generally they all want no more than 3 metres of tails.

 

[7029 dave]

Has an 3pole isolator been fitted In meter box.? If so run out from there to your switchfuse in cupboard.

 

[davesparks]

Has an 3pole isolator been fitted In meter box.? If so run out from there to your switchfuse in cupboard.

He'll still have the issue of it being more than 3 metres though

 

[7029 dave]

He'll still have the issue of it being more than 3 metres though

But he said it was only 3m or 4m to said location.

 

[Rockingit]

Dave - I'm thinking along the lines of a 125/3+N on a bit of DIN rail in a 4way enc. Reckon that would fit??

 

[jbsparks]

Trying to get and answer back from the designers is hopless (probable because the have be paid in full), meter box is already a "3 phase meter box" the problem is the depth of the meter box, you could just about squeeze it in but the door doesn't shut because of the handle isolation.
Locating it in control cupboard is optional providing DNO is happy with is but to me seems pointless locating a switch fuse 3 meters away from the cut out but if it solves a problem.

 

[jbsparks]

No isolator fitted as yet, just the three phase head. The switch fuse would be 3-4 meters away if the tails were run under the insulation/underfloor heating/screed

 

[UKMeterman]

Hi, try looking for the 4 pole 125A version of http://www.engineering.schneider-electric.dk/Attachments/ed/cat/catalog_c120_h.pdf.pdf WARNING check the PSSC against the circuit breaker rating both phase to phase faults and phase to N. Discuss with Schneider technical and the DNO if it is going in an external meter box you do need pollution degree 3 kit. They may have alternatives.

 

[jbsparks]

thanks I will take a look

 

[UKMeterman]

Due to the likely PSSC I am now suggesting you may need to go down the moulded case CB route, give Schnider a call.