2 Showers

stanmike · Posted: Wed Aug 16, 2006 9:30 pm Post Subject: 2 Showers

I have a 9.5 kw shower currently, and want to add an additional 9.5Kw shower unit, after doing the calcs the consumer unit is not capable of running two showers at the same time. - Is there a way around this ?. Reading through the forum an interlock has been mentioned - are they any good ? - where can i get more information ? - Any ideas ?..Thanks

Pens · Posted: Wed Aug 16, 2006 9:33 pm Post Subject:

It may be possible. What size is your main incomer fuse?

breezer · Posted: Wed Aug 16, 2006 9:37 pm Post Subject: Re: 2 Showers

stanmike wrote:

I have a 9.5 kw shower currently, and want to add an additional 9.5Kw shower unit, after doing the calcs the consumer unit is not capable of running two showers at the same time. - Is there a way around this ?. Reading through the forum an interlock has been mentioned - are they any good ? - where can i get more information ? - Any ideas ?..Thanks

interlock means only one shower at a time can run.

the other thing to consider is water pressure, you may not have enough to run 2 showers at same time

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ebee · Posted: Thu Aug 17, 2006 5:08 am Post Subject:

The only way I can see an interlock is one or two contactors/mains relays monitoring the heating element voltage on the showers(s) unless a simple manual DP changeover switch is used .
any different ideas?

Pens · Posted: Thu Aug 17, 2006 4:23 pm Post Subject:

He could use a Castell interlock on the shower room doors

Joking aside, if the incomer is 100amp with a few switchgear changes (assuming there is enough mains pressure) there should not be a problem

Spark123 · Posted: Thu Aug 17, 2006 4:26 pm Post Subject:

Pensdown wrote:

He could use a Castell interlock on the shower room doors

Adam_151 · Posted: Thu Aug 17, 2006 7:33 pm Post Subject:

Yeah if 100A fuse, then I'd put a fair bet on it never blowing in practice, though I'd be tempted to put it on a separate CU, to avoid stressing the incommer and bus bars

[I'd have thought, like cables, CUs would be built with 1.45 x design current for conventional time built in, and you are not going to be exceeding the design current of a modern CU for anywhere near that time unlesss you want to use both showers at once for quite a while, all the while space heating the garden/growing pot in the attic/working on quantum physics with your particle accelerator]

stanmike · Posted: Thu Aug 17, 2006 9:18 pm Post Subject: 2 shower

mains incomer is 100A, plenty of mains water pressure. I could add a c/u for the shower but still think that over all load ( taking diversity into account ) is too great for the supply.

tommo2 · Posted: Fri Aug 18, 2006 3:39 am Post Subject:

Any good wholesaler will sell you the interlock gear so that only one shower is on at one time.
There are 2 types:
1. Priority- a pullcord switch in the main bathroom controls a changeover contactor, which energises shower in main bathroom and de-energises shower in other room. Main disadvantage is anyone in the main bathroom can turn off your other shower without warning. Also, if they leave their pullcord on, then you will have no shower. It is fairly cheap though (around #50 for materials).

2. Non-priority - both showers have their own dedicated contactors which are interlocked. Whichever shower is operated first stays energised until it is turned off. (sort of like first come first served). The other shower cannot be turned until the other is finished. Around 150 for materials.

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securespark · Posted: Fri Aug 18, 2006 8:37 pm Post Subject:

Pensdown wrote:

It may be possible. What size is your main incomer fuse?

Not even if main fuse is 100A.

Consumer units do not support more than one breaker of 40A capacity or greater.

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Steve · Posted: Fri Aug 18, 2006 9:50 pm Post Subject:

securespark wrote:

Pensdown wrote:

It may be possible. What size is your main incomer fuse?

Not even if main fuse is 100A.

Consumer units do not support more than one breaker of 40A capacity or greater.

not even a 3-phase board converted to single phase?

Adam_151 · Posted: Fri Aug 18, 2006 9:57 pm Post Subject:

securespark wrote:

Consumer units do not support more than one breaker of 40A capacity or greater.

Thats something I've heard branded aout a few times, but I've yet to see anything to that effect in the technical data putout by CU makers, maybe its legend that dates from when wylex standard boards had one 45A position and carries onto this day and refuses to die?

I must admit I can't see the physics of it myself, if any way could have a 50A breaker, then each tab on the bus must be rated to 50A, the backbone of the bus must be rated to carry 100A, so I really cannot see what the difference is between 2x showers on 2 x 40A breakers and 4 x20A ovens on 4 x 20A breakers

securespark · Posted: Fri Aug 18, 2006 11:02 pm Post Subject:

Think it was GE. Def read it in someone's prod lit...

Think about it. Two showers pulling 80A. A cooker, a ring or 3. Won't be long before 100 could be exceeded...

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Pens · Posted: Sat Aug 19, 2006 1:31 pm Post Subject:

Pensdown wrote:

Joking aside, if the incomer is 100amp with a few switchgear changes (assuming there is enough mains pressure) there should not be a problem

I'm with Adam, I also can't see problem even if it means fitting another small CU via some henley blocks