Main isolation by local REC

[cliffed]

How come us electricians have to put in metal Db’s,they come along & put in a plastic isolater,for us to connect to.

 

[Octopus]

Its one of those glorious grey areas ........

A bit like how come commercial sites can still have plastic CU's

 

[Risteard]

How come us electricians have to put in metal Db’s,they come along & put in a plastic isolater,for us to connect to.

A number of reasons:

(1) The DNO is subject to ESQCR and not BS7671.
(2) An isolator on its own (an isolated isolator if you will(!)) can be argued not to be a similar switchgear assembly to a DBO to BS EN 61439-3.

 

[Octopus]

^^

Its a big shame that the muppets at the IET didn't spell this out when AMD3 CU's were forced on the domestic sector

 

[SparkyChick]

I'm starting a rewire next week and I've decided to not take any chances for the isolator so I'm fitting one of these:-

EM220 - 2 Module Metal Enclosure IP20 rated 145 x 80 x 62mm with Lid for Circuit Protection - https://www.sparksdirect.co.uk/2-module-metal-enclosure-ip20-rated-145-x-80-x-62mm-with-lid-for-circuit-protection#.WoX0IDvLiUk

The intake and isolator are under the stairs, so definitely a good reason to err on the side of caution.

 

[buzzlightyear]

I'm starting a rewire next week and I've decided to not take any chances for the isolator so I'm fitting one of these:-

why ?

 

[SparkyChick]

why ?

Why a metal enclosure or why am I fitting an isolator?

 

[buzzlightyear]

Why a metal enclosure or why am I fitting an isolator

both !

 

[SparkyChick]

Because an isolator makes life easier for the next poor sod to work on an installation and when I'm changing boards etc. I generally fit one.

Metal because whilst the argument can be had that an isolator doesn't fit the rules because it's not an assembly akin to a distribution board, it is a grey area and I can see it from both sides. The regs aren't clear, simples. So, if I'm fitting in a meter cupboard I'll use the standard plastic enclosure, but in this case it's going under the stairs... the only exit route from the first floor, so I've elected to fit a metal enclosure to minimise the risks if something does go wrong.

 

[Octopus]

Sparkychick .... Could you offer your thoughts to the IET , as your logic can't be flawed ..... And it would remove grey and introduce black and white !

 

[buzzlightyear]

any isolator up front before the new c/u does not require a metal ,
but if you are happy ,then go for it ,

 

[buzzlightyear]

And it would remove grey and introduce black and white !

in Sparkychick case pink &white .

 

[Deleted member 26818]

I'm starting a rewire next week and I've decided to not take any chances for the isolator so I'm fitting one of these:-

EM220 - 2 Module Metal Enclosure IP20 rated 145 x 80 x 62mm with Lid for Circuit Protection - https://www.sparksdirect.co.uk/2-module-metal-enclosure-ip20-rated-145-x-80-x-62mm-with-lid-for-circuit-protection#.WoX0IDvLiUk

The intake and isolator are under the stairs, so definitely a good reason to err on the side of caution.

Does it comply with the required standard?

 

[marconi]

I vaguely remember reading the report which argued for metal CUs in the domestic environment and thought the evidence did not support the abandonment of plastic. Rather the problem/evidence argued for terminals with two screws and a torque screwdriver to tighten them sufficiently well to secure the conductors. And an edict to include some instruction on making such terminations properly in electrician training and the inclusion of checks on connection security in inspection and testing.

 

[SparkyChick]

any isolator up front before the new c/u does not require a metal ,
but if you are happy ,then go for it ,

Well, I respectfully disagree.

When I had a dilemma about this previously, I asked WPD about it and why they fit plastic regardless... the only reason I was given was because they weren't working to BS7671.

Whilst a single isolator may not constitute a type tested arrangement of equipment like a distribution board, personally I feel a metal enclosure for this job offers a better chance of proving I took all reasonable precautions to ensure the safety of the installation should the unthinkable happen. I like to sleep at night.

I've looked at standards for the REC2S isolator... even the Wylex documentation for it doesn't specify any standards to which it complies. However, the REC2S features a standard 2 pole isolator to BS EN 60947-3, so yes, my arrangement will meet that standard because I'm using a standard BS EN 60947-3 double pole 100A isolator. In terms of the seals that are present on a REC2S enclosure, since these are on the metered side of the supply, the seals serve little purpose other than to prevent access for the uninitiated.

If there is a standard which defines what a supply isolator should be, then I'd like to know what it is please

As for terminations... I would like to see double screws return as it's far to easy to loosen a cage clamp. I typically flatten the tails with pliers, tighten them, wiggle, retighten and then periodically check them as I work on the board. I always check them when I'm inspecting and testing and this has revealed numerous loose terminations (including a 40A cooker circuit which miraculously had not suffered any overheating).