Supply for bathroom fittings

Trying to work out how & what cable to run to supply various bathroom & shower room fittings.

The fittings are:

shower - 1 x extractor fan: connected via local fused connector and isolating switch outside the room

shower - 1 x shower pump (MIRA) ideally I'd prefer this to be completely disconnectable for total isolation, eg via flat-pin 13A style plug into a BS1363 socket located outside the bathroom. (Other suggestions welcome)

shower - 1 x heated towel rail - connected as the extractor fan

bathroom - 1 x extractor: connected the same as the shower one

bathroom - 1 x heated towel rail - connected as the extractor fan

Hotwater pump (outside bathroom near shower pump) - similar connection to the shower pump.

All to be supplied from a spare RCD slot. Question is what is the ideal way of cabling this supply? Radial or ring? If radial what is the minimum circuit rating given that BS1363 sockets are in-circuit?

For working purposes am assuming max load to be 6A but actual max amps likely to be far less.

Any and all suggestions and advice most welcome

Reply to
freeway_rider_813
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On 7 Mar 2007 02:58:04 -0800 someone who may be freeway_rider snipped-for-privacy@hotmail.com wrote this:-

Connect it to a nearby lighting or power circuit as appropriate via a double pole switch or switched fused connector depending on circumstances.

Why on earth would you want to do this? Connect it to a power circuit via a switched fused connector. If really keen also put a 5A round pin plug and socket arrangement in.

Connect it to a power circuit via a switched fused connector.

Connect it to a lighting or power circuit as appropriate via a double pole switch or switched fused connector depending on circumstances.

Connect it to a power circuit via a switched fused connector.

Connect it to a power circuit via a switched fused connector.

The above makes assumptions about where the devices are located in relation to baths and showers. In some circumstances RCDs may be necessary.

Why? Are the rooms near to the consumer unit?

In my view the fact that you have asked these two elementary questions indicates that you do not have the competence to design the installation yourself.

My suggestion is that you get someone who is competent to design it. You may not like this suggestion and I'm sure I will be criticised for making it, but that's tough.

Reply to
David Hansen

You have not said what type of extractor... if it is one with a run on timer that is activated via the light switch then the extractor will need to be powered from the same lighting circuit. You would also need a three pole isolator switch (neutral, live, switched live), and probably a fused connection unit as well (many fans require protection at 3A). The FCU and isolator can be in the same room as the fan in zone 3. If fitted outside the room, the fan isolator technically ought to be a lockable type (the logic being if you can't see it while working on the fan, then you need a way to ensure it is not turned back on again!)

If it is in the bathroom, then a FCU would be the usual solution. That gives you full isolation anyway. Using a plug and socket would only really make sense when the whole pump is located outside the bathroom.

Something else to consider when using a plug and socket connection is that you also disconnect the earth connection to the pump should you unplug it - typically the pump itself would have its supplementary equipotential bonding provided via the earth in its supply cable, so you would be in effect removing the pump from the equipotential zone.

Depends on the total load. Some shower rails are low current draw (i.e. under 300W) and can be powered from the lighting circuit, although there is no particular reason to do it this way unless getting power elsewhere would be very difficult. A switched FCU from a power circuit would be more usual.

yup

as per other towel rail

as previously discussed.

By "RCD Slot" I take it you mean a spare way on a RCD protected consumer unit?

Ring final circuits are intended for the provision of general purpose power sockets. They work very well where you want to cover big areas and have variable and diverse loads. That is not what we are talking about here where all the loads are known and tend to be fixed, so radial would be more appropriate.

The smallest "standard" radial would usually be a 16A circuit. The individual FCUs at the connection points will allow devices requiring protection at a lower rating to be connected.

Reply to
John Rumm

Many thanks for the comments and advice by yourself and John Rumm.

Most helpful.

but it is the most elementary questions which always require the deepest reasoning and thus the most complex answers......

Indeed differences between your own approach and John's indicate there is no single definitive connection method/design for my problem.

One aspect that I am still unhappy about is the use of switched connection units to isolate the shower pump. For me that is a safety hazard. In my view there should be visible isolation during pump maintenance. Mira pumps do have a bonding tag so the question of maintaining bonding whilst unpluigged does not arise. It is also the connection method suggested in a post on this issue some years ago in this group. The simplest form of complete visible isolation would be a plug that can be withdrawn.

I was airing first thoughts about my problem and quite expecting to have various shortcomings pointed out. Thank you again.

indicates that you do not have the competence to design

You may be in good company there. My old Prof would quite likely have agreed with you, says I, dusting thick dust off a degree cert in elect engineering....

It is the incompetent who only see one way of solving a problem; don't ask for other opinions; and plough on regardless of not fully understanding the theoretical and practical aspects of a chosen implementation.

Competent people ask on uk.d-i-y!

Thanks again

Reply to
freeway_rider_813

As with many issues of this type it will partly be dictated by circumstance and what makes most sense give the actual layout of the room and circuits, and also the loading on the circuits imposed elsewhere.

Well in many cases the pumps are installed in the "special location" and hence this is a moot point since general purpose sockets are not permitted in practical terms.

If you are positioning the pump outside the bathroom then you can do it either way - the more usual being with a switched FCU. The FCU is a dual pole switch with adequate contact separation and hence provides isolation. The switch will make it visible what state it is in, and the fuse may be withdrawn for extra confidence.

Personally I generally draw reassurance from people asking questions, others may instead be worried. Such is life. Much of the time one is reading between the lines anyway trying to work out how and where to pitch an answer.

Reply to
John Rumm

On 13 Mar 2007 15:57:32 -0700 someone who may be freeway_rider snipped-for-privacy@hotmail.com wrote this:-

The Wiring Regulations are generally not a straightjacket. They do have some fundamentals, but provided these are complied with they rightly allow any solution that is practical and provides a suitable degree of safety.

The problem with that view is where would you end it? Would every house have a big plug to connect it to the external supply, would pylon routes have very big plugs at each end?

If not having a plug and socket is not a safety hazard in these situations why do anything different with a pump? Why the different approach?

I'll repeat what I typed. I meant it then and I mean it now. The fact that you have asked two elementary questions indicates you do not have the competence to design the installation yourself. It may be that with enough work you become competent enough to design the installation yourself.

Indeed.

Only up to a point. Were someone to come to a group discussing the works of Mr Shakespeare and started off by asking what books he wrote then they would most likely be told to do some of the elementary work themselves and come back when they had done so.

Reply to
David Hansen

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