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Workshop paper works


L Plate

Question

any good idea please:

1) Example where a 3 way alternative switched lighting circuit may be used.

2) why is it important that the neutral is NOT connected to the switch and state any noticeable symtoms that would be displayed when you carry out your testing..

thanks again guys for your help

have a nice evening to all

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No need to apologies Robin....

It's one o them things that happens from time to time...

I believe the correct term is...

some did a bit of a "Pushy-Shovey" while you were still posting!:DBlushing:x:)

That injuns the worst for it.

Batty

;)

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1) on a stairway or corridor

2) because if the nuetral is switched then you have a permanent live even when switch is thrown and if it is a case of someone suffering an electric shock this would put the rescuer at risk

r1+r2 test operate switch and the reading should alternate between open & closed circuit.

r2 test should be continuous whatever position of the switch

r2+rn test should be continuous whatever position of the switch

wig

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1) normally found on corridoors, with multiple door entries.

All switches outside hotel door ways will be intermediate switching.

This is the single most common use for intermediate switching.

2) Neutrals terminated at any switch can and often are mistaken for a switched live (without sleeving to denote live).

Also if connected would complete a closed circuit between nuetral and live.

Connection by deliberate or accidental/fault could cause an explosive reaction and damage the cable beyond reasonable repair.

During dead testing you would notice a continuity between nuetral and live.

You would also record a fault with insulation testing between nuetral and live.

All these faults would be recorded and found during initial testing on a dead circuit before energizing.

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No 1.

long corridor with 2 way switches at either end and an intermediate switch somewhere in between dependant on layout.

No2 Switching the neutral will not isolate the supply to the load and also not allowed in regs.

When doing test method 1 R1 + R2 for continuity of cpc using a low reading ohmeter this also proves polarity and verifies that the Line conductor is being switched.

Now say for example you were testing for R1 + R2 at a light switch but somebody had wired the light fitting (3 plate) incorrectly ie they took the switch feed from the neutral, connected the lamp to the switched neutral and live loop in terminal.

This would result in open cct results when testing between the live terminal and earth at the switch, regardless of which way the switch was operated.

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oops sorry for similar answers to other posters, no one had replied when I started typing.

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Now say for example you were testing for R1 + R2 at a light switch but somebody had wired the light fitting (3 plate) incorrectly ie they took the switch feed from the neutral, connected the lamp to the switched neutral and live loop in terminal.

This would result in open cct results when testing between the live terminal and earth at the switch, regardless of which way the switch was operated.

I have a fault like this that was picked up on a pir, booked in to rectify on Saturday morning.

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oops sorry for similar answers to other posters, no one had replied when I started typing.

No need to apologies Robin....

It's one o them things that happens from time to time...

I believe the correct term is...

some did a bit of a "Pushy-Shovey" while you were still posting!:DBlushing:x:)

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