Best Way to Wire 2 Electric Showers (Same Mains Power Supply, separate building - allow feed to auto switch)

[InsulatingTape]

Hi All,

I currently have an electric shower in the house and I am looking to connect another in a chalet, which is approx 50 meters away from the house.

The chalet is fed from the main board of the house. There is a 3x16 SWA cable coming from the house to feed the chalet.

What is the best way to wire the 2 showers to allow the feed to automatically switch between both showers as required, but won't allow both showers to come on at the same time?

I'm aware of the priority/non-priority units but this would need a new cable to go from the house to the chalet which I'm looking to avoid. There is also a risk with an additional cable that if I turn off the main power to the chalet from the house, this cable could still be live in the chalet.

 

[pc1966]

I doubt there is a simple "off the shelf" solution.

If you don't actually need the 3 cores of SWA for earth/CPC reasons, then you could arrange one core for a more traditional shower priority unit, but you would need to have triple-pole switching at both ends to allow a single action to isolate both systems. It is a very uncomfortable option and really is in the "borrowed neutral" territory so I can't see it being considered acceptable practice just to save on another cable run.

The most obvious option would be to monitor the chalet power draw and if above, say, 20A to inhibit the house shower from going on. But that would allow the chalet user to kill the house shower at will by going for a shower there.

But looking at the various options and how they might be implemented, I suspect you might find a 2nd cable run is cheaper. You still have the isolation issues, but you could use a 3P+N switch as in-effect 2*DP in parallel to allow safe isolation as needed.

 

[Wilko]

Hi - you might look at a Garo CV8-PS shower priority unit. But the problem is potentially all power to the Chalet may be cut when the house shower is operated, I’m not sure.

 

[pc1966]

Hi - you might look at a Garo CV8-PS shower priority unit. But the problem is potentially all power to the Chalet may be cut when the house shower is operated, I’m not sure.

You could put the lights & TV on a UPS and hope they don't go for too long a shower

But again the cost (both new and on-going) will quickly exceed that of a 2nd run of SWA I suspect

 

[Taylortwocities]

I dont know what the hot water requirement is in the chalet? Are there other hot water needs?

For an all electric option, I would go for a small unvented water tank (Megaflo, etc) with a 3KW immersion heater. Size it for a couple of showers worth of water.

 

[Risteard]

I doubt there is a simple "off the shelf" solution.

If you don't actually need the 3 cores of SWA for earth/CPC reasons, then you could arrange one core for a more traditional shower priority unit, but you would need to have triple-pole switching at both ends to allow a single action to isolate both systems. It is a very uncomfortable option and really is in the "borrowed neutral" territory so I can't see it being considered acceptable practice just to save on another cable run.

The most obvious option would be to monitor the chalet power draw and if above, say, 20A to inhibit the house shower from going on. But that would allow the chalet user to kill the house shower at will by going for a shower there.

But looking at the various options and how they might be implemented, I suspect you might find a 2nd cable run is cheaper. You still have the isolation issues, but you could use a 3P+N switch as in-effect 2*DP in parallel to allow safe isolation as needed.

You cannot remark conductors in the south of Ireland except in a 7-core or greater cable.

Anyhow these are Restricted Electrical Works and must be performed by a REC.

 

[Taylortwocities]

His profile says he is
“ Practising Electrician (Qualified - Domestic or Commercial etc”

Are you going to have him arrested?

 

[pc1966]

You cannot remark conductors in the south of Ireland except in a 7-core or greater cable.

Anyhow these are Restricted Electrical Works and must be performed by a REC.

Ah, sorry did not notice the country!