A friend of mine has a caravan she wants to use for commercial purposes next to the house and needs a caravan hookup. I wanted to talk through the installation with you guys please.
Before I go on, a bit of background about me. I have taken and passed the 16th Edition and Inspection and Test. I know we're onto the 17th Ed now but I do have electrical qualifications and am normally well disposed towards discussing issues like these.
The property is served by an old Wylex BS1363 Consumer Unit that is very lightly used. From what I can establish there seems to be only one or perhaps 2 ring mains and a lighting circuit. Cooker, water heating, shower etc is all gas/combi boiler. So, with diversity there is certainly plenty of capacity for it.
We don't know what the earthing arrangements are for the supply, except that it is not a TT earthing system. We know if it is a PME then an earth rod will be needed for that circuit or the supply to the caravan. There is a chance it could be TNS but I'm thinking I will have to install a TT earth for that circuit only.
Now, the caravan hookup point comes with its own RCBO so I am told. Hence I was looking to use a suitable way from the Consumer Unit, protected by a 16 Amp mini switch and run a 2.5mm T and E cable from the CU along the inside of the house in surface mounted trunking to afford suitable protection, and through the wall directly behind and into the hookup. The 16mm earth to the copper rod would be connected to the hookup.
My only area of confusion is at what point in the new circuit to I split off the earths. One will be connected to the earthing system in the house whereas the other will be connected to the TT system. I am aware that the two need to be electrically isolated.
My take would be that the electrical isolation would need to be at the point where is the RCD or RCBO is. That way the part of the circuit that is not isolated when this trips is not served by a TT earth with a high Earth Loop Impedance. Hence the cable in the house would be served by the earthing system for the main supply and the hook up point the other side of the RCD would be served via the TT earth.
Would this be correct?
BTW, I am told that the 17th Edition regs doesn't actually cover a hookup at the side of the house, but only caravan sites, so my chat with the IET today centred around I think the EW regs.
The LABC would be notified of this.
Thanks
Before I go on, a bit of background about me. I have taken and passed the 16th Edition and Inspection and Test. I know we're onto the 17th Ed now but I do have electrical qualifications and am normally well disposed towards discussing issues like these.
The property is served by an old Wylex BS1363 Consumer Unit that is very lightly used. From what I can establish there seems to be only one or perhaps 2 ring mains and a lighting circuit. Cooker, water heating, shower etc is all gas/combi boiler. So, with diversity there is certainly plenty of capacity for it.
We don't know what the earthing arrangements are for the supply, except that it is not a TT earthing system. We know if it is a PME then an earth rod will be needed for that circuit or the supply to the caravan. There is a chance it could be TNS but I'm thinking I will have to install a TT earth for that circuit only.
Now, the caravan hookup point comes with its own RCBO so I am told. Hence I was looking to use a suitable way from the Consumer Unit, protected by a 16 Amp mini switch and run a 2.5mm T and E cable from the CU along the inside of the house in surface mounted trunking to afford suitable protection, and through the wall directly behind and into the hookup. The 16mm earth to the copper rod would be connected to the hookup.
My only area of confusion is at what point in the new circuit to I split off the earths. One will be connected to the earthing system in the house whereas the other will be connected to the TT system. I am aware that the two need to be electrically isolated.
My take would be that the electrical isolation would need to be at the point where is the RCD or RCBO is. That way the part of the circuit that is not isolated when this trips is not served by a TT earth with a high Earth Loop Impedance. Hence the cable in the house would be served by the earthing system for the main supply and the hook up point the other side of the RCD would be served via the TT earth.
Would this be correct?
BTW, I am told that the 17th Edition regs doesn't actually cover a hookup at the side of the house, but only caravan sites, so my chat with the IET today centred around I think the EW regs.
The LABC would be notified of this.
Thanks