MCB/RCBO Lock off Kit

[Jupiter01]

My preference is to switch off at the mains when making some changes but on a few occasions this prolonged outage hasn't been practical and I have tested and isolated an individual circuit. In this situation, I understand that I should be using a lock and sign at the consumer unit.

Can someone please provide a recommendation on what I can purchase for this purpose?

Thanks in advance.

 

[333rocky333]

Is it for Trade use or just your own Consumer unit, if the latter you just need a cheap one for less than a fiver, as opposed to a kit that i s a lot dearer

 

[Jupiter01]

My own use but sometimes I get roped into doing stuff for extended family...
Something reasonably priced would be perfect.

 

[AndyPRK]

 

[ericmark]

As I understand it permitted with TN but not with TT.

 

[333rocky333]

If its just casual use at your home then something like this fits virtually all circuit breakers not just wylex.
You can use your own small padlock and if you want labels i believe you can buy them too

https://www.ebay.co.uk/itm/222643485513

 

[Jupiter01]

If its just casual use at your home then something like this fits virtually all circuit breakers not just wylex.
You can use your own small padlock and if you want labels i believe you can buy them too

https://www.ebay.co.uk/itm/222643485513

Is this the same thing? This kit includes the padlock and label

 

[securespark]

As I understand it permitted with TN but not with TT.

What is this in reference to, eric?

 

[JohnW2]

What is this in reference to, eric?

Judging by his previous writings, I'm assuming that he's referring to the fact that, per BS7671, 'isolation' should be double-pole in TT installations, but can be just single-pole (i.e. just the L) in TN ones. However, other than for a few 'Jobsworths', I doubt that all that many people even know it says that, let alone practice it!

Kind Regards, John

 

[securespark]

I indeed do.

But the lock off can be used on the main switch also?

 

[JohnW2]

I indeed do.

You "do" know that BS7671 says that, or you "do" practice it - or both?

But the lock off can be used on the main switch also?

Many can. However, eric's post followed immediately after one linking to three videos relating to locking off SP devices, so perhaps that's what he meant?

Kind Regards, John

 

[securespark]

Yes I know SP isolation is not to be used on TT installations and yes I practice DP isolation on such installations.

 

[JohnW2]

Yes I know SP isolation is not to be used on TT installations and yes I practice DP isolation on such installations.

Thanks for clarifying. That presumably means killing at least half of an installation (with a DP RCD), if not the whole installation (with a Main Switch, if there are no RCDs or all-SP RCBOs), which must often be somewhat of an inconvenience.

As a matter of interest, why do you feel [thinking electrically (not of 'the regs')] that DP isolation is necessary with TT but not with TN-S? I know what the regs say, about this, but would be interested to know if/why you (and others) feel that an (incredibly small) theoretical 'risk' doesn't exist with (SP isolation of) TN-S as well as with TT.

Kind Regards, John

 

[ericmark]

What is this in reference to, eric?

537.2.1.1 Every circuit shall be capable of being isolated from each of the live supply conductors. In a TN-S or TN-C-S system, it is not necessary to isolate or switch the neutral conductor where it is regarded as being reliable connected to Earth by a suitably low impedance.
Provision may be made for isolation of a group of circuits by a common means. if the service conditions allow this.

So with a TT system you need double pole isolation, there are some single module width RBCO's which do switch the neutral, but as far as I know with MCB's it needs to be two module width to switch neutral, so the

device shown here technically is only good for TN systems.

As said personally not sure about isolation with TN-C-S as it seems with the likes of EV charging points that also the earth needs isolating.

 

[333rocky333]

Is this the same thing? This kit includes the padlock and label

Is what the same thing.
There are many types available and vary in cost, some plastic some metal, some tighten on the switch dolly, some hook wire into the 2 holes on the Mcb,
many of the cheap plastic ones eventually fall to bits.
For under a tenner yes you can get a padlock included, but if you have your own padlock then just the gizmo is cheaper.