G
Geoffsd
Hi,
My name is Incognito. I have hacked Geoff's pc because I am not registered on the forum.
I have to decide whether supplementary bonding is required in a bathroom where I'm working.
Horror of horrors, there is no RCD on the lighting circuit which is the only circuit in the room.
Actually, it's a very small flat and the water and gas services enter in a cupboard on the other side of the bathroom wall.
This cupboard actually houses the consumer unit as well.
The main bond obviously runs from the water and gas pipes to the consumer unit.
The water pipe immediately returns into the floorboards and runs to the bathroom and farther to the boiler.
Under the bathroom floor the cold supplies the basin, bath and w.c.
The hot returns from the boiler in plastic under the floor where it connects to copper to supply the basin and bath.
The light cpc is only three metres from the cu (it's 1.5mm² which seems to be the fashion) and so has a resistance of 36.3mΩ (0.0363Ω).
The farthest water pipe is also three metres from the supply and so has a resistance including the main bond of 2mΩ (0.002Ω) to the MET.
So, a total of only 38.3mΩ (0.0383Ω)
I think I should install supplementary bonding from the light circuit to the w.c. water pipe.
However, the bathroom is fully tiled so it would be awful to have to channel the concrete ceiling to get to the light cpc and then down the wall to the pipe.
I have heard that it is permissible to apply the supplementary bonding outside of the room so would it be acceptable to do it in the cupboard?
If it would, I could easily connect the cold pipe to the cpc there.
Wait a minute -
that would be just duplicating the main bond.
Do you think it would be alright to not apply this supplementary bond at all as it doesn't really seem to make any difference, does it?
After all, light to pipe resistance is only 0.0383Ω and with an Ia of only 30A that means the touch voltage would only be 30x0.0383 = 1.15V.
Even with a 50A shower it would only be 9.6V.
Do you think it would confuse people in the future if they don't see supplementary bonding and will they realise that the main bond is actually doing the job of supplementary as well?
Should I bond the three cold pipes in the bathroom? I could run the conductor along the pipe?
What about the plastic supplied hot pipes?
My name is Incognito. I have hacked Geoff's pc because I am not registered on the forum.
I have to decide whether supplementary bonding is required in a bathroom where I'm working.
Horror of horrors, there is no RCD on the lighting circuit which is the only circuit in the room.
Actually, it's a very small flat and the water and gas services enter in a cupboard on the other side of the bathroom wall.
This cupboard actually houses the consumer unit as well.
The main bond obviously runs from the water and gas pipes to the consumer unit.
The water pipe immediately returns into the floorboards and runs to the bathroom and farther to the boiler.
Under the bathroom floor the cold supplies the basin, bath and w.c.
The hot returns from the boiler in plastic under the floor where it connects to copper to supply the basin and bath.
The light cpc is only three metres from the cu (it's 1.5mm² which seems to be the fashion) and so has a resistance of 36.3mΩ (0.0363Ω).
The farthest water pipe is also three metres from the supply and so has a resistance including the main bond of 2mΩ (0.002Ω) to the MET.
So, a total of only 38.3mΩ (0.0383Ω)
I think I should install supplementary bonding from the light circuit to the w.c. water pipe.
However, the bathroom is fully tiled so it would be awful to have to channel the concrete ceiling to get to the light cpc and then down the wall to the pipe.
I have heard that it is permissible to apply the supplementary bonding outside of the room so would it be acceptable to do it in the cupboard?
If it would, I could easily connect the cold pipe to the cpc there.
Wait a minute -
that would be just duplicating the main bond.
Do you think it would be alright to not apply this supplementary bond at all as it doesn't really seem to make any difference, does it?
After all, light to pipe resistance is only 0.0383Ω and with an Ia of only 30A that means the touch voltage would only be 30x0.0383 = 1.15V.
Even with a 50A shower it would only be 9.6V.
Do you think it would confuse people in the future if they don't see supplementary bonding and will they realise that the main bond is actually doing the job of supplementary as well?
Should I bond the three cold pipes in the bathroom? I could run the conductor along the pipe?
What about the plastic supplied hot pipes?
