End of line..

[tigerpaul]

I've been testing on a commercial installation where all lights are sat in the ceiling grid and then flexed back to a central LCM. One LCM per room/area.
The LCM is then flexed into a klix plug+socket on a conduit.

Now we're being asked to test r1+r2 and Zs at the klix socket. (as it's easier and were up against it at the minute) But this is not taking into account the additional resistance of the flexes away to the light fittings. So it's not truly end of line is it?

Surely I am right when I say the measurements should be taken at the last fitting? I know i am right really, I just come to get feedback and other opinions from you guys..

 

[Deleted member 26818]

Yes, should be at the furthest point.
Does the LCM have a fuse?

 

[tigerpaul]

Ah yes there is a small fuse in the LCM, I've seen it in there but I havent checked what size it is.

 

[Deleted member 26818]

You only need to test up to the LCM then.
These set ups, usually have all the leads the same length.
Disconnect one of the leads to an LCM, then use that as a test lead.
Plug it into the last point on each circuit, and test at the end of the lead.
When you've finished all the circuits, re-connect the lead.

 

[tigerpaul]

All the leads are different lengths, and it's not one lead per fitting either. Sometimes there are up to 3 fittings per lead.

 

[Deleted member 26818]

Three light fittings per lead, or three LCMs?

 

[bugsy]

It's a hybrid ( cheap n cheerfull )
Test to the LCM ( flex is not part of the fixed installation ( in my humble opinion)

 

[tigerpaul]

Three light fittings per lead, or three LCMs?

Some places have one flex going from LCM to fitting and then looping off to feed other fittings. Up to 3 at a time.

 

[tigerpaul]

It's a hybrid ( cheap n cheerfull )
Test to the LCM ( flex is not part of the fixed installation ( in my humble opinion)

But it is fixed though isnt it really.

 

[i=p/u]

you as the inspector can make a judgment of reasoanbly practical.. so maybe test from where you say and note it

 

[Deleted member 26818]

The LCM is fused, that fuse protects the circuit down stream from it.
Your Zs are required to confirm that the Circuit Protective Device will operate in the specified times.
It's the same as with an FCU.

 

[bugsy]

We only test to LCM , when you test a ring do you test the appliances plugged into it?

 

[tigerpaul]

We only test to LCM , when you test a ring do you test the appliances plugged into it?

No because the devices plugged into it are always going to be random. But the lights in the ceiling are going to stay. And if anyone gets a belt, then most likely that is where it will be.

I get the point though about the fuse in the LCM protecting everything downstream. That hadn't occured to me as I'd forgotten it was there.