Earthing in old houses

awishawash

I was just wondering what is generally done seein as 80% of older houses in Ireland have no earthing in their lighting circuits. Is a re-wire necessary?

davelerave

it depends on: if all else is in order ie:your wiring and "main earthing" is ok a sparkie could upgrade your lighting circuits.you'd need to get it checked.
are you putting in metal fittings?

awishawash

Putting a fan in a small bathroom, going to an fcu.I dont think its enough to earth it to the fcu though?Going to bring an earth from that to the ceiling rose to the fusebox. Was just wondering what was generally done when an earthing point wasnt available locally.

davelerave

if its the standard white 3-pole fcu and the standard double insulated fan i wouldn't be too worried about earthing.there's often little point running out earths in a very old house unless the earthrod and neutralizing are done and it can make the bathroom less safe .if its newer with grey pvc cabling and main earthing then no prob provide them .
if theres a ceiling rose in the bathroom that can be swapped for a 2d 16/28 watt fitting

awishawash

Hey davelerave thanks for the help, just noticed it is double insulated requiring no earthing. And I'm not gonna use the switched live so I'll just use a DP fcu. The ceiling rose in the bathroom I will have to replace with a junction box going to a globe light fitting I got free.:) , that unfortunately just has L/N connections. With condensation in a bathroom ceiling is it safe to have a junction box in the void?
Just another quick question. If a halogen light states it is a 240v product, and my lighting circuit is 230v on my multimeter, doesnt that mean I cannot connect it?

Stoner

using that light fitting at 230V is fine.

I assume that you would be using the switched live and not the permanant live with your fan, ie the fan will switch on/off when the light is switched on/off.
If you have to use a junction box them make sure its a decent one, an OBO box with 15Amp connectors would do the job or the brown lighting junction boxes. Most Globe fittings have no earths as the fitting does not conduct, just leave the earth in a spare connnector in the box so that if you ever need it it will be ready to go, junction boxes are never a great idea but the terminals on a lot of globe fittings are too small to loop a cable off so you have little choice but to use a junction box.

awishawash

Thanks for the post stoner, yeah i meant the L1 on the fan.
With regards that 230v halogen light, should I earth it back to the fusebox?At the moment it is just connected into a junction box.
Also with regards metal light switches, I have one except the backbox is a plastic one, so as its a two way, going to another switch using t+e, Ive connected the earth to the metal backbox there. Should this also be wired back to the fusebox to earth it? Do you see my confusion yet?Can things be earthed without going to the fusebox.
Also, on a side note, I've heard of voltage drops, and today in the morning the multimeter was reading a consistent 230v at each point. In the evening it was a consistent 221v. Is this normal or does it indicate a fault?

awishawash

Just a little update, I did my homework yesterday and understand earthing now so thats grand, where necessary link it so it goes back into the earth rod(via fusebox), also voltage drops tend to happen the more square footage your circuit covers, I think it wavers anyway, but the drop that happened with me is that I added around 12 meters of cable on to an outside light.
So ta again for the help!:v: :v: