oven and shower on same fuse

[thevet]

My landlord is replacing my kitchen and during the process I have discovered that the old oven (single) and the shower were connected to the same fuse.

I am now concerned that the landlord is planning to leave me with the new oven (a larger double oven) and the shower still connected to the same fuse. Is this just bad practice or actually illegal?

 

[ban-all-sheds]

What sort of shower is it? It's bad practice, and contravenes the wiring regulations, but that does not make it illegal per se.

It may be illegal because of other laws governing rented accommodation in Scotland and/or if it is unsafe.

What are the ratings of the two appliances, what is the rating of the fuse/MCB, what size is the cable, and is it installed in insulation anywhere, or bunched with other cables?

 

[ColJack]

it's illegal in so much as it contravenes Section 4.5 of Schedule 5 of "The Building ( Scotland ) Regulations 2004"..

Electrical safety
4.5 Every building must be designed and constructed in such a way that the electrical installation does not-

(a) threaten the health and safety of the people in, and around, the building; and

(b) become a source of fire.

 

[securespark]

It may be badly designed but not pose the threats you list.

 

[thevet]

The shower is an 8year old mira sport - so could be anything between 8Kw and 10Kw. I dont know what the rating of the new oven is as it hasn't been delivered yet. At the moment all I know is that it is a modern electric double oven.

Most of the wiring appears to be 6mm. The wiring from the shower and cooker go to the only RCD fuse - which is 30mA. There are about 4 fuse boxes grouped together but only one of them is modern. The wire from the oven is routed with the earth cables.

It looks like the shower was put in properly (about 8years ago) and then the oven was put in less so (about 2.5 years ago).

The kitchen fitter seems keen to get the new oven wired into a new RCD fuse - there is space for one more fuse in the newer RCD box - but:
- the tails in the box have been cut too short
- he seems to be getting some resistance from the landlord

Anybody know a good online source for checking exactly what the regulations for this are?

 

[sparkyspike]

I'm afraid I'm not up on the Scottish regs, particularly those concerning rented accomodation, but you could try here.

However, it doesn't sound like a big job. The tails can be easily extended inside the RCD box and a second breaker is going to cost about a fiver, taking minutes to fit. I don't see why your landlord would baulk at that. It's in his interest just as much as yours.

The trouble is with bad design such as this, is that you can overload the circuit without actually tripping the breaker. For this reason the two circuits need to be divided up. Perhaps you could explain this to the landlord.

 

[ColJack]

define "most of" in respect to the wiring?
what size breaker is it on..? it cannot only go the an RCD, it has to have overload protection so there must be a fuse or breaker somewhere in the line, unless the RCD is actually an RCBO..

 

[thevet]

ColJack
"most" = all the bits that I can see (but a lot is under the floor or in a plastic conduit that runs up to the fuse box).

The wire from the shower and the wire from the cooker enter a modern fusebox which has two switches - one "Main" red one marked 63A and one smaller black one marked 30mA.

Sparkyspike
Thanks for the link - unfortunately, all the information on that site is rather general and not detailed enough on wiring regs to answer my question.

 

[ban-all-sheds]

The wire from the shower and the wire from the cooker enter a modern fusebox which has two switches - one "Main" red one marked 63A and one smaller black one marked 30mA.

How/from where is that CU supplied?

Photos would be useful.

If you really do have no overcurrent protection (other than the service fuse) on the shower/cooker circuit then that is a Very Bad Thing™, and must be fixed asap.

 

[sparkyspike]

The wire from the shower and the wire from the cooker enter a modern fusebox which has two switches - one "Main" red one marked 63A and one smaller black one marked 30mA.

Sounds like an RCBO. Does it have any other markings? e.g. B32A? A second RCBO would do the trick.

 

[thevet]

The black switch is marked RCBO

Here are two pictures:
- one of the jumble of boxes and wires that hides in the fuse cupboard
- one of the specific unit that the shower and oven are wired into.

View media item 14175

View media item 14176

 

[davelx]

Very sloppy installation job on that shower CU! Should have mounted both devices touching and put a blank in.

Unusual so see shower feed done that way round I think - Generally a DP RCD is used as the incomer and a normal MCB for fault protection. But I guess this way works almost as well. The single way CU next to that looks to be supplied direct from the meter, so not RCD protected - is that the oven feed?

Are those VIR tails I see? - if the rest of the wiring is similar it's probably time for a rewire. Could we have as shot showing the incomer and the service head and main earth, with the wiring from there to the meter and in the Henleys (the black boxes)?