Lighting with no CPC and installing new CU (Domestic)

[SJD]

I have the ESC’s guide to replacing a CU where the lighting circuits have no CPC, and this says the initial approach should be to persuade the customer to upgrade the circuit to provide CPCs. If that fails, the guide then includes a risk assessment table (at the back), where it is allowed to proceed with the CU replacement if certain conditions are met (like no class 1 fittings, for example).

My question is, in practice, for those out there meeting this situation on a regular basis, what is the typical outcome (assuming the circuit meets insulation test requirements)?

Do you generally persuade the customer to upgrade the circuit (or decline to do the job)?
And if you do upgrade the circuit, do you typically rewire with new T&E, or instead fit a separate CPC and use the existing wiring?
Or are you happy to remove any class 1 fittings, place a warning notice, and proceed with the CU replacement with the existing wiring as is?

I'm thinking of an inhabited property, where costs and disruption are a concern, and all the customer originally wanted was a new CU to replace an old fuse box.

 

[oldtimer]

No if I were that concerned I would buy these switch that have plastic covers on the screw hole but what I am trying to put over and as we all knew you cannot backdate the regs remember the guys who said it was ok to leave a lighting circuit without a cpc inplace as long as class II and warning signs were heeded are not going to declare NO you must get this rewired or we will send in the electrical police just aint going to happen I myself was asked to put up some Class I fitting in a property but said sorry you have no earth at the lights Ahh they said you just want more work out of me nope was the reply I only do small electrical work and repairs rewires ,kitchens, extensions I dont do so I do not get any financial gain saying this to you .

2 weeks later got a text All sorted found someone who was willing to put my lights up and I am surprised you make a living by rejecting work like this.

I replied yes I agree but a least I can sleep at night

 

[somersetsparks]

Most houses from this era have the metal pattressess with plastic lugs, which provide no earth continuity to the pattress, They are a pain as the threads strip incredibly easy. IF it hasn't I beleive placcy 3.5mm screws are available.

 

[Guitarist]

Most houses from this era have the metal pattressess with plastic lugs, which provide no earth continuity to the pattress, They are a pain as the threads strip incredibly easy. IF it hasn't I beleive placcy 3.5mm screws are available.

You are correct, nylon screws are available.

 

[morph]

how does a new board with RCD make the lighting circuit safer ???

 

[somersetsparks]

how does a new board with RCD make the lighting circuit safer ???

If you were to get a shock from toughing a live conductor, and that shock was 30ma or over the rcd would still operate

 

[morph]

If you were to get a shock from toughing a live conductor, and that shock was 30ma or over the rcd would still operate

but the fittings are plastic and there is no earth , get me ?

 

[SJD]

but the fittings are plastic and there is no earth , get me ?

So for example, you are standing on the edge of the metal bath with no shoes, while you change the light bulb, and accidentally touch a live conductor, and had left the switch on?

 

[nickblake]

Changing a lamp slip and stick your fingers in the holder how many times ive heard of that happening RCD,s trip due to an inbalance and not always a fault to earth the prime example of this is Garden tools lawn mowers etc non or very few have CPC's in the cables as they are all class 2 advise upgrade the CDU and lable the boards recently done one no cpc metal back boxes plastic lugs job done house is safer elderly 86 year old lady just imagin whet the upheaval and stress that could add to her rather make her house as safe as i can

 

[EastAnglian]

I was asked to replace an existing class 1 spotlight with a brand new class 1 luminaire which the potential customer had bought. I soon discovered that the lighting circuits had no CPCs and identified a further 2 existing class 1 light fittings which were thus potentially dangerous.

After a conversation with the customer where I explained I was not able to fit their newly purchased lights and that their existing lights were potentially unsafe (which included "they have been there for 20 years and we've not had a shock") I issued a "notice of potentially unsafe installation", advised them they need class 2 fittings (a rewire was impossible financially), walked out the house and have never heard from them since!

There's no doubt they found somebody who would fit them.

What can you do?

 

[morph]

So for example, you are standing on the edge of the metal bath with no shoes, while you change the light bulb, and accidentally touch a live conductor, and had left the switch on?

lol
how can you contact a live wire in the plastic fitting ?

 

[morph]

th emower may be class 2 but as the blade cuts the cable it makes contact ot earth
an rcd can only work with an earth , so an rcd does not help a light circuit with no earth
just playing devils advocate

 

[SJD]

lol
how can you contact a live wire in the plastic fitting ?

Umm, I did not say "wire", I said "conductor", as in an exposed pin that contacts the light bulb. If this does not make sense, I give up.

 

[morph]

Umm, I did not say "wire", I said "conductor", as in an exposed pin that contacts the light bulb. If this does not make sense, I give up.

what exposed conductor?
its class 2
you see my point ?

 

[SJD]

what exposed conductor?
its class 2
you see my point ?

No, I really don't see your point!
A light pendant with bayonet fitting has two round pins that can have 230V on at least one of them at times.
When there is no bulb in the fitting, they are exposed.

 

[EastAnglian]

an rcd can only work with an earth

An RCD works by detecting a difference between the currents flowing in the Line & Neutral conductors of a protected circuit, it doesn't care what creates that imbalance! Of course, an earth fault will cause an imbalance of currents but so will shared neutrals being fed from different sides of a dual RCD.

Hence providing a path for current to flow from either of the live pins in a plastic light fitting by sticking your finger in it while stood in the bath is likely to trip an RCD (but you try it rather than me :cheesy: )