testing requirements

[marky1]

Hi

There is a small sub board in kitchen which feeds cooker, sockets & light in kitchen only. Customer has been advised to get 63a main switch changed to a 63a 30mA rcd main switch.

Do I test for Zs & RCD trip times only on each circuit as i'm not interferring with existing circuits plus Ze or do i have to do full test.

Thanks in advance

 

[Evans Electric]

Do you mean you are fitting the RCD ? It reads like someone else has advised .

I think you would have to check the three outgoing circuits M8.

 

[marky1]

Sorry for any confusion

Yea they want me to replace main switch with RCD main switch, but i'm unsure on whether i need to do full test as per EIC or part tests as i'm not interferring with existing circuits. First time i've had to do this.

The customer was advised, hence why they have asked me to do the work,

cheers

 

[Evans Electric]

The problem is once you modify the 3 way CU I believe you are deemed to be "the last one " to touch it and so become responsible for those three circuits , although you have made it considerably safer by inserting an RCD. You'd have to check the 3 cts because you are now saying "Those are safe" . You don't know for certain that the earths are connected .

I went to replace 3 light fittings a few weeks back , in my road, modern wiring ,looking good, one twin/E at light , its a doddle , no its not , the earth is not earth .

Empty room above, lift floor, JB doing the 3 plate and all the earths neatly snipped off . It shouldn't happen but it does and as we often say in here , you can never assume anything in this trade .

The culture today is test everything that doesn't salute back, and issue cert to cover your ass. On saying that its surely just a Minor Works but because its a kitchen you'd have to notify it. I'm sure BB will be really interested.

The worst of the light fitting job was that I went home , took a shower , knock on the door , neighbour says theres water coming through the ceiling .

I'd scraped the side of his heating main circs. with the floorboard nail . OOOoooooohhh Noooo !!!!

 

[Zeespark]

Is the house on a TT System? if not I wouldn't use and RCD as front end protection.

AndyGuinness

 

[steptoe]

third the price of 3X RCBOs though,

 

[marky1]

Thanks guys, makes sense wot ur saying.

Yea TT system,

I know its not ideal putting RCD up front but tought it better than no rcd as only 3 circuits on board & alot cheaper than rcbo's.

il test all 3 circuits to cover my arse

 

[Power Ball]

If it helps why not use the rcbo's that are for sale on this site, I have used them at the same price as a mcb. You can't beat that price and they are good quality

Chas

 

[marky1]

2 b honest didn't no u cud buy them on here, also not sure if they will fit? coz the board is quite small, but i will check measurements.

where do i go on the forum to look at them?

cheers

 

[steptoe]

do you have a 100mA front end marky1 ?

 

[marky1]

Hi steptoe

No, the sub board & main board are fed via a henley block

 

[steptoe]

is the sub board at source also then?

and IMHO, (and it is only an opinion, as the forum is split on this) SP RCBOs are not adequate protection for TT installs.

 

[marky1]

no, the sub board is about 2 mtrs away in diff room.

why do you say SP RCBO's are not adequate protection for TT system?? if you don't mind me asking what do you class as adequate protection??

 

[NozSpark]

So is there any RCD protection in the property at all?

Is the entire installation TT?

 

[steptoe]

if the sub is in a different room then IMO the sub-main to it requires a 100mA front end and the cable requires OCPD,

this really sounds like a poorly designed installation.

there has been a lot of differing views on this, but I am of the opinion that TT requires DP protection, quite a few other members are of the opinion that SP protection is adequate though,

the choice is yours as to what YOU deem adequate protection,

its your name on the test certificate.

 

[marky1]

thank you for your valued input, i will take on board what you say.

The installation comprises of 100amp isolator feeding henley block. from here it feeds main board which has a 100a 30mA rcd main switch with x8 mcb's. The henley block also feeds a 2nd board in the kitchen 2 mtrs away which has a 63a main switch with 3 mcb's. The whole installation is TT system.

I agree it is poor as it also has no Main bonding to either oil or water services!! This was noted on the EIC from a previous NICEIC sparky. I have informed the customer that there is various work required to bring it up to standard.

I am with Elecsa and due to renew my Part P soon so will ask what there veiw is on SP RCBO with ref TT system

Thanks again guys, really appreciate your views

 

[steptoe]

HOLY F,,,,,,

you have an EIC issued by an NICEIC spark that simply says there are NO MEBs on a TT install and he didnt see an issue with this?!

---------- Post Auto-Merged at 21:24 ---------- Previous post was made at 21:23 ----------

marky1, are your consumer units plastic or metal?

 

[marky1]

only got to see EIC coz i said about other work need doing ie bonding, & customer wasn't hppy coz thought i was trying to generate work, it was only when i pointed it out on EIC they realised I wasn't taking the pi55!!

both boards are plastic

 

[Power Ball]

2 b honest didn't no u cud buy them on here, also not sure if they will fit? coz the board is quite small, but i will check measurements.where do i go on the forum to look at them?

cheers

Look in the for sale section, if you don't use them on this job you might need some for another job at some time, you can always buy them then

Chas

 

[marky1]

thanks chas