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Hi guys. Need to change the fuseboard at my parents house but none of their final circuits have a cpc run to them. Obviously have an earth on the main incoming so I can get a 16mm earthing conductor up to my new 18th edition metallic consumer unit but they don’t want a rewire so none of the final circuits will be protected with an earth.

My question is will this be an issue in the functionality of the rcds? Obviously the rcd functions on an imbalance between live and neutral so as far as I’m concerned it shouldn’t be too much of an issue hopefully, just wanted to get some of your opinions on the matter.

Another issue I can see is how I’m supposed to test for disconnection times without an
earth?

Opinions would be greatly appreciated

Thanks
 

telectrix

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are you sure of the no cpc? maybe on lighting, but all other circuits should have. what's the approx. age of the installation? are the circuits in metal conduit providing the cpc's? need more info. inc. pics.

and you can't possibly go ahead with a CU install without confirming presence of CPC's
 
None of the circuits incorporate a cpc?
 
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Appreciate the speedy replies. I’ve not done any in depth research as yet, I just had a quick check of a 2 light switches while I was round there this evening having dinner. I will have to have a more in depth look now. Just thought I’d get some opinions on it before I did. I didn’t look for metal conduit in the back box but that makes perfect sense actually.
 

mattg4321

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Appreciate the speedy replies. I’ve not done any in depth research as yet, I just had a quick check of a 2 light switches while I was round there this evening having dinner. I will have to have a more in depth look now. Just thought I’d get some opinions on it before I did. I didn’t look for metal conduit in the back box but that makes perfect sense actually.
Just because the lighting circuits (or maybe just the switch drops) don't incorporate a cpc you would assume all circuits don't have one??
 
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One thing I did notice is there were 3 supply cables coming in but why would this be in a 3 bedroom house? A little over the top don’t you think?
 
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Just because the lighting circuits (or maybe just the switch drops) don't incorporate a cpc you would assume all circuits don't have one??
Thanks Matt. Maybe I should have done a bit more digging before posting. I was clearly feeling lazy
 

telectrix

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Thanks Matt. Maybe I should have done a bit more digging before posting. I was clearly feeling lazy
ytou should be able to get a government job then
 
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Just because the lighting circuits (or maybe just the switch drops) don't incorporate a cpc you would assume all circuits don't have one??
And if I remember correctly I changed a couple of lights over for them years ago and there was no earth at the ceiling rose either
 

bigspark17

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Arms
Appreciate the speedy replies. I’ve not done any in depth research as yet, I just had a quick check of a 2 light switches while I was round there this evening having dinner. I will have to have a more in depth look now. Just thought I’d get some opinions on it before I did. I didn’t look for metal conduit in the back box but that makes perfect sense actually.

If this is hoe you look into changing a cu, then my advice would be dont!!
 
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  • #16
get us some pictures. we love pictures. helps those of us that can't read grown-up writing. :p.
:D:D I’ll take some when I’m next there and get them over to you and yes maybe I should go for a job in boris cabinet ( not literally )
 

Andy78

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It could be that the lighting circuits certainly don't have a cpc. It was not a requirement before 1966. This leaves you with the wiring being 53 years young and the problem of no cpcs in the lighting circuit. A rewire would/could be advisable.
 
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If this is hoe you look into changing a cu, then my advice would be dont!!
Thanks for the advice big spark but I wasn’t looking into changing a fuseboard I was round my parents house for dinner and my dad threw it on me while I was there. I decided I’d have a VERY QUICK look while I was there and do some more digging when I have the time.
 
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It could be that the lighting circuits certainly don't have a cpc. It was not a requirement before 1966. This leaves you with the wiring being 53 years young and the problem of no cpcs in the lighting circuit. A rewire would/could be advisable.
I’ve been telling them this for over 10 years to no avail. They don’t want the mess which is understandable. They are both in their 60s so I can’t see them ever having it done.
 
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Anyone got any ideas on why there would be 3 phase going into a 3 bed house?
 

telectrix

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was normal for lighting circuits to not have cpc in 60's builds. if that's the case, it's OK to leave as is, but advise that only plastic fittings and switches should be used. if you take a light switch off, you'll probably see that the lugs for the faceplate screws are nylon, thus insulating the 3.5mm screws from the backbox.
 

telectrix

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I’ve been telling them this for over 10 years to no avail. They don’t want the mess which is understandable. They are both in their 60s so I can’t see them ever having it done.
if the wiring is in good condition, then there's no need for a rewire. maybe advise them to rewire the lightsalone, but as long as youensure insulated switches andlignts, no problem.

and the breers are taking toll.oopss maent beers.ach, gotit rigtht
 
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was normal for lighting circuits to not have cpc in 60's builds. if that's the case, it's OK to leave as is, but advise that only plastic fittings and switches should be used. if you take a light switch off, you'll probably see that the lugs for the faceplate screws are nylon, thus insulating the 3.5mm screws from the backbox.
:D:D I told my father this before he went ahead and put all new metal switches on the whole of downstairs because they “look nicer”. Head + brick wall!
 
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  • #25
if the wiring is in good condition, then there's no need for a rewire. maybe advise them to rewire the lightsalone, but as long as youensure insulated switches andlignts, no problem.

and the breers are taking toll.oopss maent beers.ach, gotit rigtht
So In terms of the functionality of the rcds, you can’t see this being an issue? I would assume that if any exposed/extraneous conductive parts do become live and someone touches them and creates a fault path, that the rcd will pick up on this imbalance regardless?
 
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  • #27
if the wiring is in good condition, then there's no need for a rewire. maybe advise them to rewire the lightsalone, but as long as youensure insulated switches andlignts, no problem.

and the breers are taking toll.oopss maent beers.ach, gotit rigtht
Up stairs lighting maybe wouldn’t be too much of an issue but downstairs means floorboards up and they won’t have it
 

Andy78

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:D:D I told my father this before he went ahead and put all new metal switches on the whole of downstairs because they “look nicer”. Head + brick wall!
And they're still like this, and you being a sparky ? Have you been peeking at the will or something ?
 

telectrix

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So In terms of the functionality of the rcds, you can’t see this being an issue? I would assume that if any exposed/extraneous conductive parts do become live and someone touches them and creates a fault path, that the rcd will pick up on this imbalance regardless?
yep. RCDs don't need earths/cpc's . the human body provides the earth path to provide the imbalance.
 
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as they say. you can't educate pork.
Not entirely sure how to take that :D
 

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