In the laundry room, I currently have 1 socket, with 1 underlying wire of 1.5 mm2 of section. This connects to a 16A circuit breaker. In the country I live in, voltage is 230V.

I need to install 3 machines in this laundry room:

  • washing machine : 2100 W
  • dryer : 2700 W
  • tank water heater : 2000 W

This is obviously way too much for this 1 wire. The ideal solution would be to get a new wire from the fusebox, but that is hard to do, and would require redecorating large portions of the house, which I just can't do at the moment.

So I thought of a solution. Could I replace the wire that currently goes from the fusebox to the socket, and replacing it by say a 4mm2 one?

I would put 3 sockets with this underlying 4mm2 wire, and plug the 3 machines on these sockets.

So 2 questions:

  1. I read online that the tank water heater should be on its own wire, so that would not be the case in my scenario. Why do they suggest that, and is it somewhat reasonable to not follow this direction ?
  2. Knowing that there are about 6m between the fusebox and the socket, how easy would it be for someone with no experience at all to to replace the existing cable by a new one, thicker?
  • 1
    How is replacing a thin wire with a thick wire easy but adding a new wire hard? Commented Jan 21, 2021 at 21:43
  • 1
    Because there is currently a plastic tube (conduit?) going from the fuse box to the socket. I can remove the wire in this plastic tube, and replace it by a thicker wire. Does that make sense?
    – DevShark
    Commented Jan 21, 2021 at 22:00
  • 1
    I think the plastic tube is probably too small to accomodate a new wire, that’s why I am thinking of replacing the cable, not simply adding a new one.
    – DevShark
    Commented Jan 21, 2021 at 22:01
  • thicker wires may not fit in the conduit.
    – Jasen
    Commented Jan 21, 2021 at 22:19
  • OK, a "Cable" is several "wires" inside a common sheath (wrapper). Cables inside conduits make for rather inefficient use of conduit capacity. I would extend the conduit all the way into the panel, and then extend the conduit to a "junction box" somewhere in the laundry room. This junction box could actually have one of the receptacles on it. Once the conduit is continuous from panel to box, I'd pull in individual wires of whatever type are in common use in your country, and those will fit no problem. Commented Jan 22, 2021 at 0:43

1 Answer 1


In general upgrading the wire is an acceptable solution, but you will probably also need to have new breakers at the laundry end of the wire.

You will need to put a new breaker box in the laundry at the end of the wire and have breakers for your three appliances there. there are probably rules about which parts of the room are allowed to have the breaker box.

Alternatively if your house has a three phase service you could just run two more lives in the conduit (from the other two phases), and share the existing neutral and ground wires, that's assuming there's room in the conduit for two more wires.

  • Thanks for that. Adding a new breaker box sounds a little bit difficult though. Do you think it's hard, for someone with little electrical work experience?
    – DevShark
    Commented Jan 21, 2021 at 23:42
  • yes, here the that's beyond the scope allowed by a homeowner.
    – Jasen
    Commented Jan 21, 2021 at 23:49
  • Ok. What do you think of the solution of not adding a new breaker box then, but simply running the cable from the main breaker box, through the conduit, directly to a single set of 3 plugs? Is that reasonable?
    – DevShark
    Commented Jan 22, 2021 at 0:47

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