Part P Testing

[Thermo]

No im not trying to start a debate!

Last year i had a loft extension done and i carried out the wiring of the lighting and the power to it. The building inspector obviously wants the work signed off, and im just in the process arranging for the testing to be carried out.

Im just wondering from a practical point of view what is actually tested and how it is done? (without too much technical mumbo jumbo!)

 

[Adam_151]

There is inspection as well as testing, but from a testing point of view:

Dead tests:

Continuity of CPCs, this is normally done by connecting phase to cpc at the DB and measureing between them at distant point to give you the R1+R2 value

Ring continuity, measure all three conductors end to end, to prove its not broken, then cross connections are made between the legs and go around the ring to check for bridges and spurs off spurs, etc

Insulation resistance: Insulation resistance is measured while testing with 500vCD (unplug your computer first!)

Polarity: check that phase and neutral not reversed and switches are in the phase, the R1+R2 test proves this as well and polarity is normally done at the same time as continuity, just involves obtaining r1+r2 readings at more points


Live tests:

Polarity of supply : check the supply is the correct polarity, its not unknown for the DNO to mess it up

Loop: Earth loop impedance (Zs) is measured to make sure disconnection times are acheived, this can be measured at furthest point on all circuits, or it can be measured at the board (Ze) and added to the worst case R1+R2 value for each circuit

RCD: RCD should trip in 200ms at 1xtrip current, 40ms at 5xtrip current (test only needed on 30ma or lower RCDS) and not trip at all at 0.5x trip current, tests need to be repeated on 0 and 180 degrees

 

[ebee]

When you say you`re just in the process of arranging for it to be tested.
If the LABC require it to be tested then they must arrange (and pay for) it not you. You have already paid LABC fees which cover it (and do not let them tell you otherwise) by virtue of the fact a building inspector is involved.

See loads of threads here about part p.

Otrherwise, the previous advice about what a tester might want is pretty good.

I assume the inspector viewd your first fix. He shuold have done so

 

[Thermo]

thanks chaps

weve actually used one of these licenesd companies for the building regs rather than the labc, so dont want to get into all that, spent many a night reading the part p debates!

My question answered clearly and succinctly, once again i thank you!