3phase lift, borrowed neutral. What code?

[fletchflash]

Hi all,

Just after some help with a code for PIR.

Jobs at a nursing home, 3phase lift supplied by a pvc 3 core and earth (2.5mm). The circuit is protected by a 20amp mcb, then goes into a small board with a 60 amp mcb, acting as an isolator for the lift, no means of isolating the neutral. Next to the board is a fused spur on 5amp cellar lights circuit. The neutral for the lift then comes from lift board, into this fused spur, using the 1.5mm lighting circuit as a borrowed neutral.

what code should i give it? 1 or 2?

cheers

 

[Andy™]

code 2

unless TT, there is no need for neutral to be isolated

 

[Manator]

TP Lift would require no neutral unless it was TP&N, the neutral may not be borrowed?

 

[fletchflash]

its a TP&N, definatley borrowed.

thanks for help

 

[Andy™]

TP Lift would require no neutral unless it was TP&N, the neutral may not be borrowed?

motor wont require neutral, but the control gear may

 

[green-hornet]

I would go with code 2, looks like someone decided to do a quick fix for the lighting

 

[spinlondon]

Are lifts covered by BS7671, or by some other BS number?

 

[Andy™]

Are lifts covered by BS7671, or by some other BS number?

the actual lift may have other regs, but the wiring to it will still be under 7671. and possibly the wiring within.

 

[Manator]

The supply and associated wiring will still be BS7671 the actual lift and control gear would be BS ISO 22201:2009 as with many standards there will be crossovers in all standards.

 

[fletchflash]

green hornet- its other way round mate, its the lift using the lighting circuits neutral.

 

[green-hornet]

green hornet- its other way round mate, its the lift using the lighting circuits neutral.

OMG Thats even worse, did you find out why they did it that way?

 

[steptoe]

its prob been a 3ph lift at some stage and now the new(?) panel needs a N so they have stole it from the light.

this is as G-H says, V bad.

what size N is it, 1mm I expect as its for the light,

and the supply for the lift is protected by what, 20A, so what can the N carry?

undersize cables, disconnection! code 1 for me.

 

[Manator]

its prob been a 3ph lift at some stage and now the new(?) panel needs a N so they have stole it from the light.this is as G-H says, V bad.

what size N is it, 1mm I expect as its for the light,

and the supply for the lift is protected by what, 20A, so what can the N carry?

undersize cables, disconnection! code 1 for me.

Very interesting question which GH may have been trying to suggest, but not as articulate.

 

[fletchflash]

sorry not been online for a while.

The wiring seems to look newer than the lift, so not sure if a 3ph has been replaced with3ph&n. I didnt disconnect it, gave it a code 2. I didnt open the lift panel, just the isolatoir as an o/s company services the lift. I came to the conclusion that it probably was for control gear, there was no sign of heat damage to the connection in light circuit. not sure if i done the right thing, slightly worried, but the whole place is to be rewired by the end of this year