Electricity supply to shower

[peter]

My home is a semi detached chalet bungalow originally built in 1956. The upper storey was created some 25 years ago by adding a back flat roof conversion to a previous semi- detached bungalow. The main bathroom is downstairs on the (front) north east corner of the building and the mains electrical panel is in a kitchen pantry at the south east corner of the building. The switch panel is a recent Wylex unit with spare slots. Upstairs bathroom provision consists of a cloakroom with a toilet and wash handbasin.

We are completely refitting the main bathroom and as part of this plan to have a 10.5 kw electric shower fitted as our aging central heating boiler is a backboiler and we wish to keep all options open (including a combination boiler) when we consider replacement in due course. Given that the upstairs flooring consists of 8x4 foot chipboard sheets we are daunted by the disruption which is likely to arise from the exercise of taking a new power supply from the switch panel to the bathroom. We realise that the cabling required for a 10.5kw shower is thick and inflexible but would like to use a high rated shower in order to enjoy good performance. Looking at the possible options:-

1. Would it be legal / practical to take the wiring along the outside of the building in conduit - this would appear to be a straightforward run of some

25 feet. The wall involved is adjacent to the (concrete) driveway and is covered for the majority of the length by a carport? Would we be likely to encounter problems in bending the cable sufficiently to cope with the angles involved?

1. If the above is not an approved approach and we do have to cope with the disruption upstairs - what would be the easiest way of gaining access through the floor? The chipboard (19mm) lays on 38mmx225mm joists which run at right angles to the direction in which the cable has to be taken. The original downstairs ceiling joists run in the direction the cable has to take.
2. Any other ideas?

Any help gratefully accepted.

[Jim Alexander]

while I think about the cable routing question, would just highlight one issue. Intrigued by the passing reference to a combination boiler as if that rules out future non-electric shower options. Well the combi would be

24kW minimum, probably 28kW, perhaps 32kW. Your electric shower will be 10.5kW, OK IMHO as a backup but not even up to combi standards.

Jim A

[Jim Alexander]

are you saying you can't access the eaves space above the first floor joists, the space between the ceiling joists or even the (usual) space between the new floor joists and the orginal ceiling joists? any space under the ground floor?

Jim A

[Christian McArdle]

This is permitted and practical, but can be ugly if the wall is currently good looking. A similar alternative is that external runs can be made in Hi-Tuf, or SWA armoured cable. However, Hi-Tuf is probably not permitted in your case, as mechanical protection is required under a car port, so armoured cable or metal conduit would be indicated. If the possible ugliness is mitigated by the current appearance of the area, then this is probably your best option with the least work involved.

It may be easier to run through the ceiling space and patch the ceiling, than lift the chipboard.

Sometimes there is space between the edge of the flooring and the wall, which you can get access to by removing the skirting boards. However, there's no guarantee and it is not acceptable to run actually behind the skirting above floor level. It will only work if there is a slot behind the flooring that the cable can be dropped into. I've used this technique several times, but been foiled a couple.

If you do decide to go under the floor, one method is to router out a few inspection panels, which can then be filled with proprietary hatches to allow subsequent access later and allow flooring (i.e. carpet or lino, but not tiles) to be relaid. You will normally find that there is space underneath the joists on a suspended floor, so the direction of joists doesn't matter. Your only problem is getting the cable past any sleeper walls. They are normally perforated for air circulation reasons and I have usually been successful poking a long garden cane through a hole and retrieving string to pull cable at the next panel. You can go a good 4 or 5 metres between panels, given long enough canes and arms.

A tip to working in such cases is to borrow (if you don't have one) a camcorder. Drop it down below the floor, turn the shooting light on, angle the screen up and you can see where you are poking. You can go one better and duct tape it to an off road RC car and feed signals back to a monitor if you really want! Don't forget to tie your string to it first, though!

Christian.

[Tony Bryer]

Assuming the OP can - or knows someone who can - terminate it properly is MICC acceptable in this position: much less conspicuous.

[David Hansen]

On Tue, 22 Aug 2006 18:21:47 +0100 someone who may be Tony Bryer wrote this:-

Good idea, provided one does not use an orange or red sheath on the stuff which would make it rather conspicuous. No problem running this outside.