Electrcial advice guys if you have time

kathleenbilly · Aug 1, 2009

Hello to those looking in,

I have been a member but this is my first post,

I have this now finished my college courses and hold.

level 2 2330
level 3 2330
2391 Inspection and testing
17th edition BS 7671

I have now got a job with a company and have been thrown in the deep end but will do my best and learn quickly, i hope to get mostly help from here and i'm sure i will be fine.

Some of my questions will be basic so excuse them if the answer is obvious i'd still rather ask.

My first question ,

I wiring lighting within PVC Conduit using singles 1.5mm etc

After wiring the first set of lights and picking up the constant live to light switch (from the DB) to take to my next light switch to begin to wire the next set of lights which will be two way for example.

The neutral which starts from the DB and goes directly into the lights can i pick this neutral up at any point to continue onto my next set of lights? Or does it need to be the same length or taken at the same point where i pick up the main live again from the first light switch?

Basically what i asking is does the neutral and live feed/switch wires need to be the same length or does it not matter how long the neutral is or isn't. Is it ok so long as it completes the circuit?

This happened at college when i wired lamps up and didn't bring the neutral back into the same conduit although it came back to the board i was told it causes some sort of inbalance because it is different lengths?

hope this sort of make sense and any advice or clarity appreciated.
KB

chocolate · Aug 1, 2009

When wiring in singles, the total length of the N conductors will ( in most cases ) be shorter than the L conductors. That is because they follow different routes.

Your L's go from DB to each switch in turn. From each switch is your switched-live which goes directly to the light fitting.

Your N's go from DB to each light fitting directly, in turn.

CPCs go everywhere.

So I guess . . . yes . . you have a difference in length, but an 'imbalance'. Not sure what they were getting at. Wgeb you do your dead tests, you do two continuity tests - (1) link L and CPC at board and measure resistance at all relevant points, and (2) link N and CPC at board and again measure resistance at all relevant points. The highest readings obtained won't be the same due to the difference in path length. There's nothing wrong with it. As long as results are good !!!

Congrats on all the qualifications.

kathleenbilly · Aug 2, 2009

Thanks for looking in i understand completely what you have said. I don't need to worry about the lengths of the neutral and will continue to the next set of lights and not worry about lengths anymore.

Thanks also for the test info normally i would do just a R1+R2 test but will now also do RN+R2 (CPC)

This job will be my first self wiring and will go towards my NVQ Level 3 which i'm doing on-line with quickstep.

Thanks again chocolate for your advice,

KB

gunner · Aug 2, 2009

well done with qualifications.agree with chocolate about imbalances,neutral runs in form of loop from ceiling rose to ceiling rose,ie ground circuit,upstairs circuit etc etc