here's a nice little problem i've just found. watch out for this one. installing a twin rcd 17th edition cu i put the two lighting circuits on separate rcds (minimising inconvenience). switch everything on and both rcds trip. it was common practice when i was a boy to wire the two gang switch at the bottom of the stairs with a switch wire from the hall light and strappers to the upstairs switch. the switch feed fed both sides of the two gang. this means that the landing light has a live from the downstairs circuit but a neutral from the upstairs circuit. this unbalances both rcds. we're going to find this a lot.
"borrowed" switch feed
- Thread starter EarthWire
- Start date
edward current
Active Member
good point...... its funny how seperate rcds minimise inconvenience, why could people possibly need lights on a rcd anyway?????
edward current
Active Member
i know the regs but can see the point
more advanced advance sparky!
New Member
here's a nice little problem i've just found. watch
out for this one. installing a twin rcd 17th edition
cu i put the two lighting circuits on separate rcds
(minimising inconvenience). switch everything on and
both rcds trip. it was common practice when i was a
boy to wire the two gang switch at the bottom of the
stairs with a switch wire from the hall light and
strappers to the upstairs switch. the switch feed fed
both sides of the two gang. this means that the
landing light has a live from the downstairs circuit
but a neutral from the upstairs circuit. this
unbalances both rcds. we're going to find this a lot.
Found the exact same thing this week.
Luckily for the customer it was sorted in a couple of hours.
Never seen it done this way before but will know to look out for it now.
out for this one. installing a twin rcd 17th edition
cu i put the two lighting circuits on separate rcds
(minimising inconvenience). switch everything on and
both rcds trip. it was common practice when i was a
boy to wire the two gang switch at the bottom of the
stairs with a switch wire from the hall light and
strappers to the upstairs switch. the switch feed fed
both sides of the two gang. this means that the
landing light has a live from the downstairs circuit
but a neutral from the upstairs circuit. this
unbalances both rcds. we're going to find this a lot.
Found the exact same thing this week.
Luckily for the customer it was sorted in a couple of hours.
Never seen it done this way before but will know to look out for it now.
Lester lecky
New Member
sorry... let me get this straight. You've got two lighting circuits? One upstairs and one downstairs on two seperate RCBO (RCD) circuits? Aren't you therefore "borrowing" the neutral from the upstairs lighting circuit, but the live supply is from the downstairs cirucit? is this what you're saying?
Lester lecky
New Member
I thought "borrowing" a Neutral from another lighting circuit has always been a BIG NO NO and bad practice!!??
wklivesvtime
New Member
jeez lester. He has obviously done a board change to a slit load dual rcd type - no rcbo - and withthe new regs each lighting cct on a seperate rcd. the lighting cct has a borrowen n which aint rare to say the least and its obviously upset play.
wklivesvtime
New Member
i know the regs but can see the point
A nail for example can no longer penetrate a phase and become live without disconnection. Thats the point.
A nail for example can no longer penetrate a phase and become live without disconnection. Thats the point.
wklivesvtime
New Member
seperate ccts by either supplying correct N to required point or usually eisiest is to make the landing light draw juice from the downstairs cct and before all the goobers start screaming that the landing 1st floor light will be on a downstairs cct - it will - do i care?
Its good practice to podge about in the landing lights before a board change to check for this.
Its good practice to podge about in the landing lights before a board change to check for this.
SPECIAL LOCATION
New Member
here's a nice little problem i've just found. watch
out for this one. installing a twin rcd 17th edition
cu i put the two lighting circuits on separate rcds
(minimising inconvenience). switch everything on and
both rcds trip. it was common practice <u>when i was a
boy to wire the two gang switch at the bottom of the
stairs with a switch wire from the hall light and
strappers to the upstairs switch. the switch feed fed
both sides of the two gang. this means that the
landing light has a live from the downstairs circuit
but a neutral from the upstairs circuit.</u> this
unbalances both rcds. we're going to find this a lot.
Non compliance with 16th edition! let alone 17th!!
314-01-04:
All final circuits shall be electrically separate from every other final circuit. (paraphrase)
There is a high risk of electric shock when working on circuits where two fuses can supply the same conductor. (e.g. upstairs neutral wire) BAD PRACTICE!!
When parts of circuits are joined together then it should either be;
a) joined properly to make one circuit or
b) separated properly to make two circuits.
Hopefully 17th may help identify and remedy some of these poor wiring practices...
Though they should have been picked up on Periodic inspection reports... (if any were done?).
out for this one. installing a twin rcd 17th edition
cu i put the two lighting circuits on separate rcds
(minimising inconvenience). switch everything on and
both rcds trip. it was common practice <u>when i was a
boy to wire the two gang switch at the bottom of the
stairs with a switch wire from the hall light and
strappers to the upstairs switch. the switch feed fed
both sides of the two gang. this means that the
landing light has a live from the downstairs circuit
but a neutral from the upstairs circuit.</u> this
unbalances both rcds. we're going to find this a lot.
Non compliance with 16th edition! let alone 17th!!
314-01-04:
All final circuits shall be electrically separate from every other final circuit. (paraphrase)
There is a high risk of electric shock when working on circuits where two fuses can supply the same conductor. (e.g. upstairs neutral wire) BAD PRACTICE!!
When parts of circuits are joined together then it should either be;
a) joined properly to make one circuit or
b) separated properly to make two circuits.
Hopefully 17th may help identify and remedy some of these poor wiring practices...
Though they should have been picked up on Periodic inspection reports... (if any were done?).
either run a neutral from the downstairs circuit to the landing light or run a switch feed from the upstairs circuit to the downstairs switch, feedin the two sides of the 2gang seperately. i've just worked on a house which had only one lighting circuit with 14 lighting points, some of which had been changed to fitting with several lamps. the fuse wire had been replaced with many strands of flex. i ran a 3core+earth from the cu to a jb above the landing light. the live feeds the upstairs circuit and a neutral for the upstairs circuit and a neutral from the downstairs circuit for the landing light which gets its live from the downstairs switch
more advanced advance sparky!
New Member
Its good practice to podge about in the landing
lights before a board change to check for this.
Aye i learnt me lesson.
Extra dough though.
lights before a board change to check for this.
Aye i learnt me lesson.
Extra dough though.
Lester lecky
New Member
understand its a board change for 17th etc. All very good. So i now understood correctly that lighting circuit has borrowed Neutral. So i agree, circuits with borrowed neutrals will cause serious problems with the new boards.
Hence all those electricians who have borrowed Neutrals in the past are gonna cause us electricians of today a few problems. It has always been seen as bad practice though to borrow neutrals though...The NICEIC and other bodys advise giving a CODE 1 on a PIR for a "borrowed" Neutral.
Still i agree with original post...its something to be aware of...
Hence all those electricians who have borrowed Neutrals in the past are gonna cause us electricians of today a few problems. It has always been seen as bad practice though to borrow neutrals though...The NICEIC and other bodys advise giving a CODE 1 on a PIR for a "borrowed" Neutral.
Still i agree with original post...its something to be aware of...
W
wally
Guest
Its annoying to see this but is quite common & has to be reported on with a PIR or altered if c/u change or indeed any extra work on any of the offending circuits etc. The best way to alter it will be very much dependant on the layout of the place. One option which I often use is to disconnect the neutral from the landing light & seal off in JB then run a seperate N to this landing light back to the c/u in the corresponding n tertminal. (assuming the borrowed N is concerning the 2 way landing light)
OLDER SPARKY
New Member
Really you should not be called wally - as you know better. Credit to you sir.
All those idiots using different neutral to the actual circuit want crucifying. Going back even to the 14th edition it would be wrong, I suggest even as far back as the 12th.. You will most likley find they were not time served as was the case in the not so long past. Blame it on DIY stores etc, even in the old days wholesalers were very wary of selling products to the general public.
All those idiots using different neutral to the actual circuit want crucifying. Going back even to the 14th edition it would be wrong, I suggest even as far back as the 12th.. You will most likley find they were not time served as was the case in the not so long past. Blame it on DIY stores etc, even in the old days wholesalers were very wary of selling products to the general public.