We would like to install an electric power shower in our bathroom. The location is on the wall of the cupboard where the hot water tank resides with pipes right behind the wall and high wattage electric to the immersion heater.
Would this be a major plumbing job? DIY able? If we got a Plumber in what would the ball aprk cost be?
Ta
Do you mean a pumped shower (i.e. using stored hot water), or an electrically heated shower?
Electrically speaking, in either case you will not be able to use the supply to the immersion heater in order to feed the shower. The immersion should be powered from its own circuit, probably be fused at
15A or 16A for a heater rated at perhaps 13A (3kW). In theory this would allow you to attach a small load such as a shower pump, but the IEE doesn't like it and specifically says that fixed heaters such as immersions should be supplied from their own dedicated circuits. The supply to a pump is quite small however and can quite properly be taken from a spur on your sockets circuit.If you mean an electrically heated shower then these take a *lot* more power than an immersion heater and are fed from their own dedicated circuit, usually rated between 30A (7kW) and 45A (10kW). They must also be fed via an RCD.
In the case of a shower pump, the electrical work is relatively easy and probably quite minor assuming the ring circuit isn't too far away from the location of the pump. In the case of an electrically heated shower the need to run a hefty bit of cable (6mmsq or 10mmsq) and to provide a suitable supply will make the electrical work much more onerous.
As for the plumbing, electrically heated showers just need a good cold feed. Pumped showers may need a bit more, but plumbing isn't my strong point. There have been several threads here *very* recently (in the last fortnight or so) containing advice on this issue - search for "essex flange" and you should turn up several interesting discussions.
HTH
Hwyl!
M.
Especially if you don't restrict your search to uk.d-i-y !!! ;-)
£150 - £300
Either will require the supply to be protected by an RCD.
If your cold water storage tank is in the attic a floor or so above the HW cylinder you probably don't need an Essex (or other type of) flange but can simply take your hot water feed from the pipework low down e.g. tee off from the feed to the hot tap of the bath or basin. The cold water supply will need to be from the tank in the attic too and if there isn't currently a tapping on that tank for this (i.e. if the bath's cold supply is direct from the mains) then you'll need to arrange the supply from a separate tapping on the tank. This tapping should be an inch or so lower than that feeding the hot water cylinder, but still a couple of inches above the bottom of the tank. You may have to swap over the hot and (new) cold tappings to achieve this.
It's not a major plumbing job, but can be a bit fiddly. 'DIY-able' depends on your skills, resources and experience: if you've only ever put up shelves you'll probably have trouble, if you've fitted a WC or changed taps at the back of a sink or bath you'll probaly find it OK.
Does it say that in the regs?
MBQ
It depends :-)
Electrically heated showers are fixed electrical appliances in the zones (zone 1 usually) and therefore must be supplied via an RCD.
Electrically pumped showers *may* be in the zones - where the pump is part of the wall unit / mixer - or may be completely outside the zones as in the case of a separate pump in (for example) the airing cupboard with only the tap/mixer inside the shower. In the former case the supply must be via RCD, in the latter case it isn't necessary.
Note that in the case of a pumped shower where the supply for the pump is a fused spur from a sockets circuit, there may already be a suitable RCD on the sockets circuit and no additional device is needed.
If you've never heard of bathroom zoning, there have been discussions on this group about it several times, try a search.
Hwyl!
M.
According to my on site guide, Zone 1 SELV allowed, Water heaters, showers, shower pumps allowed. other fixed equipment that can not reasonably be located elsewhere allowed if protected by a 30mA RCD.
loz34
SELV stands for "Safe Extra Low Voltage" LOZ34, so anything that runs on a SELV system is more than likely running through an isolated step down transformer to give the low voltage and ampage needed to be within "Zone 1" of a wet room area. The point of the SELV rating is to allow electronic equipment to be in an area where it might be directly splashed or come into contact with high amounts of water or steam. I don't fancy splashing water on a mains powered item while I'm standing in the bath. :-))
the point I was making is that it is NOT a requirement for showers and equipment designed to be in zone 1 to be protected by an RCD.
Loz
I understand the principle of zoning.
I was questioning the emphatic "will require". Your answer clarifies that it should be "may require" depending on circumstances.
MBQ
Sneaky, but well spotted; it's there in the wording. You are absolutely right, neither the OSG nor BS7671 make it mandatory for either a water heater or a shower pump to be RCD protected if they are designed for use in zone 1.
I suspect that this common belief is another case of John Whitfield-ism:
(The Electrician's Guide to the 16th Edition etc... Revised 6th edition, page 134)
"Water heaters and shower pumps may be installed in Zones 1 and 2, as may other equipments suitable for the conditions, provided that they have the required protection against water and are protected by an RCD with a rating of not more than 30mA."
Note how the use of the comma-separated phrase "as may..." makes it a requirement that everything must be RCD protected. In BS7671 and the OSG this information is set out as a numbered or tabulated list and it is obvious that the RCD requirement only applies to one item on that list. I suspect therefore that Whitfield's assertion that an RCD is required is due mainly to dodgy grammar.
On the other hand, there's no harm in RCD-ing the shower either...
Hwyl!
M.
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