Should I replace the MCB with an RCBO

[esspeegee]

Hi all,

Not terribly good at the part P stuff yet. Rewires and new CUs are easy but the subtleties of the smaller stuff confuses me.

Customer wants kitchen lighting changed from 1 centre light to 9 GU10 downlights. Do I need to replace the 6a MCB with an RCBO? I'd rather avoid doing so because it might throw up problems in the rest of the lighting circuit and will also add quite a chunk to the bill.

Thanks

SImon

 

[Smilers]

Every new wiring added must be RCD protected- that would be 17th regs not part peeeeee.

 

[Andy™]

Customer wants kitchen lighting changed from 1 centre light to 9 GU10 downlights. Do I need to replace the 6a MCB with an RCBO?

why do you think it needs an RCD?

---------- Post Auto-Merged at 17:50 ---------- Previous post was made at 17:50 ----------

Every new wiring added must be RCD protected- that would be 17th regs not part peeeeee.

no it doesnt.

 

[esspeegee]

i thought you'd say that. So before I can even start I got to do IR tests on the circuit. Wot a pain.

 

[Smilers]

Unless you want to go the long way round about it

 

[betty swollocks]

Cables buried in walls less than 50mm or not protected by metallic conduit need to be rcd protected

A ceiling void is not the same situation

So unless you introduce a new switch drop then an rcd isn't always required

Secondly, you should do an insulation resistance test as part of the job, as a matter of course and not just because you think the rcd might not set when you've finished!

 

[Doc Hudson]

i thought you'd say that. So before I can even start I got to do IR tests on the circuit. Wot a pain.

Not a pain. standard practice if you are not a cowboy. I cannot believe any professional electrician would ever consider extending or modifying a circuit that they have not proved the integrity of, i.e. earthing, Zs, insulation resistance etc.. Or how were you going to fill in your minor works certificate? Do the job properly and charge the customer accordingly.

Doc H.

 

[ProDave]

Hi all,Not terribly good at the part P stuff yet. Rewires and new CUs are easy but the subtleties of the smaller stuff confuses me.

Might I suggest if you are doing CU changes and rewires in England or Wales, then you SHOULD be "good at the part P stuff"

 

[OnOff]

i thought you'd say that. So before I can even start I got to do IR tests on the circuit. Wot a pain.

Yee hah! headbang

No wonder Admin wants out!

 

[esspeegee]

CUs and rewires are easy. You just test the lot. Additions and alterations are not always as clear to me.

Doc - I dont think Im a cowboy, tho I know I aint very good. A minor works cert doesn't ask for IR results, so I confess I don't do them when modifying a circuit. Betty says you don't always need supplementary protection adding, so it seems to me there's conflicting views on this.

That's why I get a little confused come seeking advice from the wise. I aint got a guvnor to go to. 6 years ago I was a desk jockey but got sacked so retrained as a domestic spark and Im still pretty rubbish, especially with the paperwork but I'm NICEIC registered and I try to get it right without being a pedant. I work alone and rely heavily on feedback from this kind of site.

.

 

[Andy™]

MWC does ask for IR results...

 

[esspeegee]

doh - So it does. Losing it

---------- Post Auto-Merged at 20:06 ---------- Previous post was made at 20:02 ----------

If I do IR across L/N but there appears to be a load in the circuit that I cant find, but L/E and N/E are clear, how should I proceed?

 

[SPECIAL LOCATION]

CUs and rewires are easy. You just test the lot. Additions and alterations are not always as clear to me. Doc - I dont think Im a cowboy, tho I know I aint very good. A minor works cert doesn't ask for IR results, so I confess I don't do them when modifying a circuit. Betty says you don't always need supplementary protection adding, so it seems to me there's conflicting views on this.

That's why I get a little confused come seeking advice from the wise. I aint got a guvnor to go to. 6 years ago I was a desk jockey but got sacked so retrained as a domestic spark and Im still pretty rubbish, especially with the paperwork but I'm NICEIC registered and I try to get it right without being a pedant. I work alone and rely heavily on feedback from this kind of site.

.

:red card

Perhaps you should invest in a copy of BS761..

And then read page 393..

Model forms

Minor works..

midway down:-

IR test results comes under the heading of "ESSENTIAL TESTS"

Its been in there for donkeys years!

Perhaps you should retrain as a Desk Jockey cuz you haven't got a clue about the basics of wiring...

Or is this another wind up??????????? headbang

This is basic testing stuff

:shakehead

---------- Post Auto-Merged at 20:20 ---------- Previous post was made at 20:19 ----------

doh - So it does. Losing it---------- Post Auto-Merged at 20:06 ---------- Previous post was made at 20:02 ----------

If I do IR across L/N but there appears to be a load in the circuit that I cant find, but L/E and N/E are clear, how should I proceed?

Call a qualified spark to do the job!!

 

[Andy™]

Get yourself an old fashioned wind up megger - strap yourself across it - that will be a pain :slap

probably wouldnt bother with the 'test', too much hassle

 

[esspeegee]

yeah, you're right of course. Although I am qualified - just goes to show the limitations of qualification eh?. Care to tell me how to proceed in this instance?

The IR thing was a mistake. I checked my minor works certs and I have been doing it. Obviously don't do many of them, obviously wasnt thinking.

Your suggestion that I jack it and go back to a desk is spot on but in the meantime, in an effort to get better at this job, all I wondered is whether extending a lighting circuit meant I had to replace the MCB with an RCBO. It just seemed to me to offer little benefit in terms of additional protection. It appears it does and that I should. Now I know, easy peasy. And yes, I'll do a MWC.

I wish I found it as easy as you to know what was right and wrong.

 

[Andy™]

yeah, you're right of course. Although I am qualified - just goes to show the limitations of qualification eh?. Care to tell me how to proceed in this instance?The IR thing was a mistake. I checked my minor works certs and I have been doing it. Obviously don't do many of them, obviously wasnt thinking.

Your suggestion that I jack it and go back to a desk is spot on but in the meantime, in an effort to get better at this job, all I wondered is whether extending a lighting circuit meant I had to replace the MCB with an RCBO. It just seemed to me to offer little benefit in terms of additional protection. It appears it does and that I should. Now I know, easy peasy. And yes, I'll do a MWC.

I wish I found it as easy as you to know what was right and wrong.

actually, if you tried readings 7671, and Betty's post, you may find you dont actually need an RCD. but then this is basic stuff, that anyone 'qualified' should know

 

[steptoe]

just goes to prove that qualified doesnt make you competent,

therefore, if you do insist on carrying on with doing electrical works of this nature, you will in fact be acting illegally, and breaking the law.

 

[philbas]

just goes to prove that qualified doesnt make you competent.

The problem these days is that been competent doesn't make you qualified, we all know you don't have a QVC (oh no that's a shopping channel) , your not a member of the RAC (no that's a breakdown service), I have it, you don't have an NVQ (I'm not sure what that is)

 

[lineman]

For what it's worth mate link L/N together and test to earth.

 

[Doc Hudson]

Thread moved as the OP is clearly struggling with basics.

Doc H.