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Hi, everyone.
I have a shower room that currently has hot water provided by a 7kw tankless water heater. The room is plumbed for hot and cold water from the domestic hot water (oil fired), but the pipe is so long (more than 60m) that it's barely warm by the time it gets there, hence the heater that is plumbed into the cold line.
The existing unit always struggled to keep the water hot enough, and it's now given up.
I inherited the existing setup which is - feed taken from the CU through a 40A mcb via 10mm cable to an secondary CU which contains an RCD. From there out through the loft space to the unit also in 10mm cable).
The main CU is 3 phase.
I've seen 11kw units that require connecting across 2 phases (ie they are 400v single phase devices).
Given that I have the power available (3 phase CU), how can I implement this correctly? I can't find anything that covers this in the 17th edition regs. Unless I missed it, it's not in the part that deals with installations in bathrooms.
I know it will need an RCD, but how is that implemented? Should/can I use a 3 phase RCD and just not use one of the poles?
I intend to get this all checked out professionally when I'm done, but I live in the middle of nowhere and getting someone to come out just for a bit of advice is a big ask.
I want to do all the legwork before I get a sparky in to finally connect it up.
Thanks
I have a shower room that currently has hot water provided by a 7kw tankless water heater. The room is plumbed for hot and cold water from the domestic hot water (oil fired), but the pipe is so long (more than 60m) that it's barely warm by the time it gets there, hence the heater that is plumbed into the cold line.
The existing unit always struggled to keep the water hot enough, and it's now given up.
I inherited the existing setup which is - feed taken from the CU through a 40A mcb via 10mm cable to an secondary CU which contains an RCD. From there out through the loft space to the unit also in 10mm cable).
The main CU is 3 phase.
I've seen 11kw units that require connecting across 2 phases (ie they are 400v single phase devices).
Given that I have the power available (3 phase CU), how can I implement this correctly? I can't find anything that covers this in the 17th edition regs. Unless I missed it, it's not in the part that deals with installations in bathrooms.
I know it will need an RCD, but how is that implemented? Should/can I use a 3 phase RCD and just not use one of the poles?
I intend to get this all checked out professionally when I'm done, but I live in the middle of nowhere and getting someone to come out just for a bit of advice is a big ask.
I want to do all the legwork before I get a sparky in to finally connect it up.
Thanks