Supply isolators

[uksparks]

Hi,

just a quick thought before I buy a load of plastic ones...

would you say that a supply isolator for the meter tails also needs to be in a metal enclosure with ref 421.1.201?

i was just about to buy another 20 isolators and it suddenly occurred to me.

 

[Richard Burns]

Take your pick of the advice floating around.
Both yes and no depending on who you talk to.

However one piece of advice that stuck is that similar assemblies should have a switch and a protective device. (which then leads to all SFCUs needing to be metal! (sorry, non combustible))
Right then an isolator has not got protective device and so is not a similar assembly.

From the intent of the regulation they are trying to do a catch all statement so that someone does not fit a series of fuses and a switch in an enclosure and say see it is not a consumer unit.
Then others have come along and muddied the water, the solar one of the AC and DC isolators being similar assemblies was one that really took the biscuit.
I think one could say that any device that houses connections for a main house supply current could then overheat because of loose connections which is why IET said they brought the regulation in, though they unaccountably failed to mention this in the regulation and should therefore be metal.

I would use plastic for this without a qualm.
(and then get hauled over the coals by the assessor!)

 

[Octopus]

Hum.. good question. As usual the muppets at the IET haven't thought through the implication of the changes they make have on the guys like us when there isn't clarity.

I did ask the IET guys at Elex last week if they were going to submit the next revision of BS 7671 to the Plain English Society for review and I don't think they took the suggestion very well!

 

[HappyHippyDad]

I would think that it will just be consumer units that just need to be metal.

The IET chap at the Elex show clearly states (in relation to what needs to be metal (or rather non combustible - thanks Richard)) that :

"its domestic and its consumer units, and consumer unit assemblies"

This is seen in the following link. The question and discussion takes place from 28.15mins - 28.47mins.

https://www.youtube.com/watch?v=nJvLT7uwO58&feature=youtu.be

 

[Stu1312]

Well the metering companies aren't planning to change to metal units for there isolators that's for sure!

which make do you currently use? We've just moved to using the Proteus EMIS range, normally not a fan of there kit but the new isolators no longer have cage clamps and two screws per termination. They are a lot better than the Wylex or MEM versions

 

[Leesparkykent]

I normally fit the hager ones as they come with a clamp top and bottom

 

[7029 dave]

No mention of it at our end, no doubt will still be fitting Wylex plastic. :smiley2:

 

[Octopus]

No mention of it at our end, no doubt will still be fitting Wylex plastic. :smiley2:

Yup.. seen that just this week.

Got customer to call you lot - "your sparky" needs to supply the isolator, so I fitted a nice metal one with my SWA terminated into it.

SSE engineer comes along, has a hissy fit about my isolator being in "their" cupboard - and he fits his Wylex REC2 (plastic) above mine.

Got to go back to run standard tails between them!

 

[uksparks]

Thanks for the replies, it's what I was thinking really. I did have to read the reg a couple of times and I also came to the conclusion it's only a switch at the end of the day.

what are the hager isolators like? I only fit hager boards so would be interested in them.

I have always fitted the Wylex REC2STT which has the twin terminals, I get them off eBay, I got about 20 last time for £10 each but can't seem to find any twin terminal ones at that price as don't really want to spend £20 on each one.

i get through quite a few as generally I fit one with every board change if practical etc.

 

[netblindpaul]

I think that you will find that once the official guidance is published, IN WRITING, that it will be metal for everything, including the REC2 type isolator, rotary isolators for solar, etc. etc.

 

[HandySparks]

I have always fitted the Wylex REC2STT which has the twin terminals...

That's interesting. I didn't know that there is a twin terminal version.

 

[Stu1312]

That's interesting. I didn't know that there is a twin terminal version.

Wylex and proteus both do them now, haven't seen the Wylex one but the proteus one is surprisingly good! Uses 3mm hex key terminals. They've even done a range of 100amp blocks as well.

http://proteusswitchgear.com/index.php/electricity-meter-isolator-switch-10.html

 

[uksparks]

Yes they are 3mm Allen key. They at really good, I way prefer having two screws over one, it's kind of a fail safe!

 

[Midwest]

Hi,

just a quick thought before I buy a load of plastic ones...

would you say that a supply isolator for the meter tails also needs to be in a metal enclosure with ref 421.1.201?

i was just about to buy another 20 isolators and it suddenly occurred to me.

I wouldn't buy a load of them, unless you can install before the 1st Jan! I asked Wylex if their were going to manufacture an A3 metal SWF, and they said one's being developed. Question, would installing in a meter box on the outside of a property, be 'within' a domestic property?