Shower timer switch

Hinton Heating · Post by **Hinton Heating** » Mon Feb 12, 2007 2:59 pm

I have been asked by a customer to replace his old 7.2kw shower.

It currently has either 4mm or 6mm braided cable supplying it.

I was thinking of putting in a 9kw shower.

what size cable would be recommended, is the old one ok?

Also the customer wants one remote timed switch, that is just switched on, then cuts the power off to the shower after say 20mins.

I can only see 16amp versions, but I guess a 9kw is going to draw more than that?

any thoughts?

Hinton Heating · Post by **Hinton Heating** » Mon Feb 12, 2007 6:39 pm

any thoughts?

sparkydude · Post by **sparkydude** » Mon Feb 12, 2007 6:40 pm

I would doubt that the existing cable is upto the job Hinton, but it depends on length of run, if it goes through insulation or is enclosed by trunking or conduit. It might be better to change the cable for a new 10.00mm cable and dont forget you will have to upgrade the bonding in the bathroom if there is nothing present at the moment. As for the timer , its possible but would be a bit expensive, using a boost timer, contactor and other bits . Why does he want the shower timed??

Nick

Hinton Heating · Post by **Hinton Heating** » Mon Feb 12, 2007 6:52 pm

Its for his elderly mother, who is forgetful, hes worried she'll leave it running all night.

if the timer cust off the power after say 30 mins, then it'll stop the water too.

sparkydude · Post by **sparkydude** » Mon Feb 12, 2007 7:01 pm

Oh right, yes it is possible to do . Is the airing cupboard near to the proposed shower location? as you will need somewhere to pick up a low amperage feed, from the immersion supply would be ideal. Basically you need a contactor rated to your shower load. All a contactor is like an industrial relay. You would use the boost switch or timer you spoke of earlier, but instead of the shower being controlled directly , you would use the timers output to control the A1 and A2 terminals on the contactor, theis will energise the coil of the contactor. The shower feed would connect in one side of the contactor and the other side of the contactor for the load. Basically the low wattage supply from the timer energises the coil in the contactor pulling the contacts in and letting the electricity through.

Hope this helps

Nick

Hinton Heating · Post by **Hinton Heating** » Mon Feb 12, 2007 7:11 pm

thats what I was thinking... will probably suggest a spring light switch like they use in the hallways of flats, which can connect to the contactor.

Its a bungalow, so its not so bad. I'm going to pass it to a spark, as its beyond my scope, and I'm a bit worried about the cable sizing, and no idea about sourcing a contactor box! 8-)

sparkydude · Post by **sparkydude** » Mon Feb 12, 2007 7:14 pm

Its not too hard, if you feel confident about it then go for it. Only problem is that Part P thing LoL You wont be able t o use a push to make switch without adding a timer relay to it as well , to keep the contacts on the contactor closed. If you want any help sizing the shower cable just shout as well as any help with connections etc,

Nick

Hinton Heating · Post by **Hinton Heating** » Mon Feb 12, 2007 7:19 pm

Cheers for the offer... As you say the Part P will cause an issue, as altering a circuit in a bathroom.

I'd rather let the spark do it, to be honest, I understand how a relay works, and the principles of switching a high current circuit, by using a "relay" and a low curent timer switch.

Jaeger_S2k · Post by **Jaeger_S2k** » Tue Feb 13, 2007 12:34 am

You could always use a second hand 3 way motorised valve switch?