Main Supply Isolator Switch (REC Switch)

[SelfBuilder101]

Thanks ericmark and sorry for the delayed response but I did a little digging.

Today I am really not sure what is permitted. Since the fire retardant consumer unit rules came in, not sure if you can have an isolator in a plastic box?

https://www.diynot.com/diy/threads/main-supply-isolator-switch-rec-switch.478031/#ixzz4Zoi1xbgl
Looking at the wording of the regulation associated with Amendment 3:

421.1.201 Within domestic (household) premises, consumer units and similar switchgear assemblies shall comply with BS EN 61439-3 and shall:

(i) have their enclosure manufactured from non-combustible material, or

(ii) be enclosed in a cabinet or enclosure constructed of non-combustible material and complying with Regulation 132.12.

NOTE 1: Ferrous metal, e.g. steel, is deemed to be an example of a non-combustible material.

NOTE 2: The implementation date for this regulation is the 1st January 2016, but does not preclude compliance with the regulation prior to that date.
​

The isolator would need to sit in the meter box so two thoughts come to mind that are relevant to you ponderings on plastic isolation switched:

1. Meter boxes (e.g. Mikras MK3 Surface Mounted) are fire retardant.
2. Meter boxes are on the outside of buildings (certainly the surface mount type) so not "within domestic (housegold) premises".

Do you think that means it would meet the requirements of Amendment 3 if in such a meter box?

 

[EFLImpudence]

It's me again with the works spanner.


How have you decided that a single switch is a "similar switchgear assembly" as a consumer unit?
By the definition of switchgear, it is not.

Is fire retardant the same as non-combustible?

The DNO/Supplier may not allow your switch in their box.


I'm not being awkward. It's been discussed at length.
No one knows the answers because the regulation doesn't really make sense.

 

[stillp]

How have you decided that a single switch is a "similar switchgear assembly" as a consumer unit?
By the definition of switchgear, it is not.

 

[securespark]

Some meters (Siemens, I think) had a 100A DP switch built in. The terminal cover was split in two: the REC side was wired up and sealed, leaving the other side with the consumer's terminals and DP switch accessible.

 

[Taylortwocities]

And for some unknown reason (but probably cost) the design of the new smart meters does not include an isolation switch.
This short-sighted decision leaves future generations of electricians and householders still having to ask the DNOs to remove seals and fuses to isolate the supply; in the event of work such as a CU change.

 

[OwainDIYer]

And for some unknown reason (but probably cost) the design of the new smart meters does not include an isolation switch.

They do however have cutoff switches so they can turn the electricity off remotely.

How long it will be before they turn the wrong switch on remotely and electrocute someone who thinks the power's off remains to be seen.

 

[ban-all-sheds]

ban-all-sheds: It would be safer for the meter installer.

They have their own methods of working which ensure their safety - they don't need a switch as you propose, and meters are not frequently installed.

I'm expecting we will be upgrading our meter to a smart meter in the near term

You do realise that no matter what they might try to make you believe, you do have the right to refuse such a meter? I suggest you exercise it.

and an isolator switch would make that easier.

1. It would not, because it will not be installed before the meter.
2. They don't need such a switch as they have their own established methods of working which allow them to install meters with no difficulty.

Regardless of that, intrinsically it has to be safer to have the option of straightforwardly isolating the supply.

No it does not, because it introduces extra joints and they are a potential source of danger.

Do meters (which I note are mostly plastic) ever catch fire?

Probably not, but if one did I suggest that by the time you notice the last thing you'd want to do would be to try and flick a switch a few inches away from a burning meter.

I just don't buy the rationale of keeping it live makes it tamper proof as I have seen loads of poles in other countries with loads of illegal taps and that would have been done when Live. Anyone minded to steal electricity wouldn't be put off by it being permanently Live.

Fair enough - don't buy it then.

It matters not one iota - whether you agree or not you will not get an isolator installed before the meter, and that's all there is to it.

You are building a house, FGS:

1. You have far more important things to worry about.
2. You are obsessing far to much about the minutiae of the electrical installation when you should be leaving that to the electrician and getting on with project managing the build.

 

[ban-all-sheds]

The isolator would need to sit in the meter box so two thoughts come to mind that are relevant to you ponderings on plastic isolation switched:

We aren't pondering.

You are, for some unfathomable reason.

Meter boxes (e.g. Mikras MK3 Surface Mounted) are fire retardant.

1. Meter boxes are on the outside of buildings (certainly the surface mount type) so not "within domestic (housegold) premises".

Do you think that means it would meet the requirements of Amendment 3 if in such a meter box?

If you carry on getting so exercised over such little things because of your febrile imagination your build is going to go catastrophically T-U.

 

[securespark]

Definition of "Switchgear" from BS7671:

An assembly of main and auxiliary switching equipment for operation, regulation, protection or other control of an electrical installation.

 

[Iggifer]

And for some unknown reason (but probably cost) the design of the new smart meters does not include an isolation switch.
This short-sighted decision leaves future generations of electricians and householders still having to ask the DNOs to remove seals and fuses to isolate the supply; in the event of work such as a CU change.

But some of them (the huge ones, forget the brand) do have an isolation facility built into the software. They have a little switch illuminated on the screen - obviously closed.

Whether this only applies to remote isolation or if you can actually use it from the meter, who knows?

You need a code to get into any menu, whether there is a special code that just lets you isolate the supply and not get into programming is another matter.

If I happen to run into a MOP anytime soon I'll try and remember to ask

 

[flameport]

do have an isolation facility built into the software.

No sane person would ever rely on computer software for isolation.

 

[Iggifer]

No sane person would ever rely on computer software for isolation.

No that's very true

 

[ban-all-sheds]

You need a code to get into any menu, whether there is a special code that just lets you isolate the supply and not get into programming is another matter.

If I happen to run into a MOP anytime soon I'll try and remember to ask

Far too much effort.

I'll wager what's left of my pension that once the prevalence of smart meters really ramps up you'll be able to find out on the Internet how to hack them.

 

[ban-all-sheds]

No sane person would ever rely on computer software for isolation.

Nor, I suspect (although I've not looked into it), would anybody who wanted to comply with the EAWR/BS7671.

 

[bernardgreen]

No sane person would ever rely on computer software for isolation.

Take the fuse(s) out and keep them ( and any spares ) in your pocket while working.