Two showers off one supply

[Philipn]

Some time ago I built a toilet and shower area at the end of my detached garage for use when doing outside DIY or gardening jobs instead of traipsing through the house with mucky clothes, etc. When I built this I ran a 6mm cable into the garage for the 8.5 kW electric shower through a 45 amp mcb.

Since then I have had a garden room built fairly close to the garage which we use occasionally to accommodate relatives and friends when they stay over. I now want to add an en-suite to this, and obviously would want to include a shower in it.

The en-suite shower will only be used very occasionally so I'd prefer to use the existing supply in the garage. The problem here, of course, would be if the two showers were both used at the same time. This would be a very unlikely event but nevertheless I'd like to come up with some way of preventing it from happening - short of standing outside the door!

Can any of you think of a way of achieving this - for example is there some kind of toggle switch available to allow either one to be supplied while switching off the other?

In the small-signal, machine control world that I inhabited before I retired we accomplished such things by the use of relays but I have no idea about such things in domestic electrics.

 

[Rpa07]

Moderators have all the fun! And I thought it was only blondes!
(Picture : Westward10 in blonde wig enjoying the best of BOTH worlds)

 

[Midwest]

If the work encompasses a whole refurbishment, doesn't need a specific notification, as long as its suitably designed, installed, inspected, tested & certified.

 

[Philipn]

OP my comment was not aimed at you.

Well, my last comment was removed, and so what I said still stands. Most of these forums seem to be largely occupied by a little holier-than-thou clique, and this one appears to be no exception. I noticed that only last week someone was unfairly attacked and patronised when asking a question about a faulty cooker.

Many thanks to those who did supply useful information, but I'll try elsewhere in future.

 

[westward10]

Your last comment was removed due to the fact it referenced the post which caused the initial problem.

 

[Intoelectrics]

Well, my last comment was removed, and so what I said still stands. Most of these forums seem to be largely occupied by a little holier-than-thou clique, and this one appears to be no exception. I noticed that only last week someone was unfairly attacked and patronised when asking a question about a faulty cooker.

Many thanks to those who did supply useful information, but I'll try elsewhere in future.

I think Westward was very fair and correct to remove the posts, it was partly in your defense. (being a moderator is a thankless job!)
This forum has lots of good members who are happy to offer sensible advise. But they also feel a duty to protect people from potential danger or injury occurring from ignorance.
I use the word "ignorance" because often people choose to ignore safety in favor of quick cheap fixes. I'm not saying this is the case in your situation, but it is very often the case and after a while some long standing members get (understandably) frustrated and may respond in a sharp, patronising manner.
You find this on most forums regardless of the content. I'm a member of quite a few different forums on a wide range of subjects and the pattern is always the same. You get the cranks and you get the job's worths. Trust me this forum tends to be one of the better ones, with very few of either.

 

[johnduffell]

Been mentioned before here; isn’t there a specific device that will only allow one shower to automatically operate at once?

Edit; something like this,
Priority & Non-Priority Shower Units | Electrical News | Meteor Electrical Ltd. - http://www.meteorelectrical.com/news/consumer-units/priority--nonpriority-shower-units/801526994

oi! you can't edit your post and steal my link

 

[Midwest]

oi! you can't edit your post and steal my link

Ehh?

 

[johnduffell]

Ehh?

you must have done the same Google search as me then!

When i posted mine yours didn't have a link, then i posted my reply with a link, then later i noticed you had the same link in your post so i was confused

 

[Santa]

With the priority/non-priority switch, you need to think carefully about which way to set them:

If the slave shower (2) is operating, and the master shower (1) is turned ON, the slave shower (2) will automatically be switched OFF, even if someone is using it.

 

[adonis2]

I don't know the distance to the ops garage and outbuilding, but is 6mm cable enough for an 8.5 shower or should it be 10mm?

 

[johnduffell]

With the priority/non-priority switch, you need to think carefully about which way to set them:

True but that seems to only apply to "priority", the confusingly named "non priority" gives priority to the one that was switched on first which will be what the OP wants

"Garo shower non priority boards. Neither shower has priority, whichever shower is on first will remain on. The second shower will not come on until the first shower is switched off."

 

[tudore]

I have experienced a similar set-up with two showers in one house. I thought a split board with each shower on a separate RCD would be OK. Now have power for both, but still not enough water pressure. So you may not need a switch: if someone tries to use the second shower while the first is in use, the pressure will drop and the thermal cutout on the first shower will cut power accordingly. So you probably won't need a switch or separate supply unless you have enough water to run both showers full power. Without that pressure, all your work will be for nothing (as mine was).