swapping like for like

voltage · Apr 5, 2011

Hi all

This is a staged scenario to get me prepared for real life installs etc.

Say i get a job which involves swapping a shower lets say for instance the shower is a 8.5kw fed by a 10mm cable the consumer unit has correct TYPE B MCB rated at 40amps
and the consumer unit is RCD protected.

So i will swap the unit for the same kw rating as before a 8.5kw

Testing ? what actual tests are involved in testing the shower ?

1/ continuity of CPC ?
2/ Insulation resistance test ?
3/ Testing of the RCD ?

any advice from you guys would be appreciated many thanks volt.

malcolmsanford · Apr 5, 2011

None what so ever is required. Nor even as it is a special location would you need to notify it under part P.

Now saying that to show a professional approach I would issue a MEIWC for the job and doing all the tests on that. IMO this shows the client that you are professional and it will have you name and address on it for future reference and hopfully future work or referral.

voltage · Apr 5, 2011

thanks malc what tests would it require ? Continuity of CPC , Insulation resistance test, and testing of the RCD ?

malcolmsanford · Apr 5, 2011

If you have a copy of the BS 7671-2008 in appendix 6 page 335 gives you a template of a MEIWC, which all types have to adopt as standard, the format may alter a little but basically they are the same.

Have a good look at the appendix it whole as it will familiarise you to the forms and how they should be used.

voltage · Apr 5, 2011

thanks will have a look now

voltage · Apr 5, 2011

Hi yeah i've read through appendix 6 on model forms and the MEIWC so the tests its saying to carry out are
Insulation resistance
Earth fault loop impedance
Polarity
RCD operation

How do you test the RCD operation on a shower circuit with the tester i no how to test it for socket outlets just plug in and test.
But where and how do you test the operation of the RCD for the shower circuit.
Any help would be appreciated thanks volt.

miner69er · Apr 5, 2011

this is a problem testing the rcd with no plug to insert and eawr state no live working is allowed. in my strange little world i can't begin to contemplate leaving live terminals hanging with croc clips on to test as i go downstairs to keep flipping the rcd back on when there could be someone else in the house.
so my solution is: as long as the R1+R2 I/R EFLI etc are all o.k then i will put my probes directly on the rcd so i can stand in front of it to flip the switch back up as it trips. the preliminary tests have already proved earth continuity etc. so i regard this as just as good as you are only checking to make sure the rcd hits its tripping times. hope that helps

Guest123 · Apr 5, 2011

The RCD test can be carried out at the RCD terminals.

You have already proved the integrity of the shower circuit with the other tests.

jaresquire · Apr 5, 2011

I think, Lenny, it is fear of the scheme inspector beheading you for throwing the main switch live with the board cover off here!

voltage · Apr 5, 2011

miner69er said:
this is a problem testing the rcd with no plug to insert and eawr state no live working is allowed. in my strange little world i can't begin to contemplate leaving live terminals hanging with croc clips on to test as i go downstairs to keep flipping the rcd back on when there could be someone else in the house.
so my solution is: as long as the R1+R2 I/R EFLI etc are all o.k then i will put my probes directly on the rcd so i can stand in front of it to flip the switch back up as it trips. the preliminary tests have already proved earth continuity etc. so i regard this as just as good as you are only checking to make sure the rcd hits its tripping times. hope that helps

That did indeed help many thanks.

Sorry for my ignorance guys but im new to this as you can tell but i want to make sure i do everything correct and be quite ---- about it

If my inspection goes well and i pass etc then im going to book my inspection and testing level 2 before im let loose on the public

Being serious i just want to make sure i know exactly what im doing and why.
All your help on my posts over the last few days really has been a great help many thanks once again to all who contribute