RCCB as main switch?

[Noob2013]

Hi all,

I have been to a property where the tails come out of the meter and into an RCCB which then feeds the main switch of the consumer unit. All circuits are protected by MCBs.

If I'm adding a new circuit, is it best put in an RCBO instead of an MCB?

Thanks

 

[Guest125]

That reg was already present even in the 16th edition, but was interpreted by a lot of sparks to mean only the OCPDs and final circuit arrangement, hence we had lot of upfront 30mA RCDs fitted to 16th Edition installs, the introduction of the 17th where RCD everything in domestic became the new fad, the rule was clarified further and implicitly applied to RCDs hence the so called dual RCD 17th edition boards, which itself was a 'kludge'

Agreed and interoperated incorrectly in my view. I think the reg is crystal clear and mentions nothing about RCDs or OCPDs.

 

[spark 68]

It wasn't stated so crystal clear in the 16th though, and like a lot of regs was open to interpretation, the RCD parts of that edition being almost an "afterthought" at least in the earlier 16th editions (pre amds), the 17th clarified it further.

 

[Guest125]

The 16th was shocking. I remember earthing radiators from the bathroom light.

 

[telectrix]

The 16th was shocking. I remember bonding radiators from the bathroom light.

corrected for you. :49:

 

[Guest77]

The 16th was shocking. I remember earthing radiators from the bathroom light.

Why would you do that?

 

[Guest125]

Why would you do that?

Because that what was being asked of us.

 

[baldsparkies]

I remember bonding with another electrician in the gents toilets at a new Asda store.
I have never gotten over it, scarred for life lads.

 

[Octopus]

531.2.5 - An RCD shall be so selected and the electrical circuits so subdivided that any protective conductor current which may be expected to occur during normal operation of the connected load(s) will be unlikely to cause unnecessary tripping of the device.

And:

314.1 - Every installation shall be divided into circuits, as necessary, to:

(i) avoid danger and minimise inconvenience in the event of a fault
(ii) facilitate safe inspection, testing and maintenance (see also Section 537)
(iii) take account of hazards that may arise from the failure or a single circuit such as a lighting circuit
(iv) reduce the possibility of unwanted tripping of RCDs due to excessive protective conductor (PE) currents not due to a fault
(v) mitigate the effects of electromagnetic disturbances (see also chapter 44)
(vi) prevent the indirect energising of a circuit intended to be isolated.

As usual BS 7671 gobbledegook

Yes I'm well aware of the regs - but in this instance we are debating the way to add a circuit to an existing install, not a new CU and not a rewire.

You do not apply BS 7671 retrospectively

BS 7671 is not statute.

So I view people like you with the "its illegal", "its unsafe", as rip off merchants at best, cowboys at worst.

 

[TJ Anderson]

BS 7671 is not statute.

.

No it isn't, but that is what we work to along with some other regulations. It is also what will be referred to by others and you will have to justify why you worked outside it. I find it easier to work within it. That is also unfair to label UKES a rip off merchant for offering to carry out work to current regulations, the customer does not have to accept it so they.

 

[Guest125]

As usual BS 7671 gobbledegook

Yes I'm well aware of the regs - but in this instance we are debating the way to add a circuit to an existing install, not a new CU and not a rewire.

You do not apply BS 7671 retrospectively

BS 7671 is not statute.

So I view people like you with the "its illegal", "its unsafe", as rip off merchants at best, cowboys at worst.

With respect you have no idea who I am mate. Best leave it like that. Ok?

 

[TJ Anderson]

Because that what was being asked of us.

Hey , I was in morrisons on the way home to pick up some cream for my haemorrhoids, walked past the fireworks display and now it is all in my hair and clothes. What should I do?

 

[Guest125]

Hey , I was in morrisons on the way home to pick up some cream for my haemorrhoids, walked past the fireworks display and now it is all in my hair and clothes. What should I do?

Haha. Speak with Dave. He directs all that. I woke up thinking of that this morning. Lol.

 

[tazz]

The 16th was shocking. I remember earthing radiators from the bathroom light.

That was the 15th Edition, when earth bonding went stupid....radiators, aluminium windows, false ceilings, sink tops, baths...etc

 

[Simlec]

Haha. Speak with Dave. He directs all that. I woke up thinking of that this morning. Lol.

If you woke up thinking of Dave, you need to get out more lol

 

[Octopus]

No it isn't, but that is what we work to along with some other regulations. It is also what will be referred to by others and you will have to justify why you worked outside it. I find it easier to work within it. That is also unfair to label UKES a rip off merchant for offering to carry out work to current regulations, the customer does not have to accept it so they.

I disagree. IF and I say IF the installation has bonding and a 30mA RCD then why would a new CU be needed? Sure offer the client 2 choices but saying it HAS to be changed is a misrepresentation of the regs.

Just saying.