Hi guys, is 1.5mm ok to use to take a spur off another socket to run a fridge on? And is a 20amp isolation switch suitable for an electric shower? Cheers in advance.
Cable sizes
- Thread starter littleleaks
- Start date
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elrobbo82
depending on the loads and cable derating factors. also you will have to refer to manufacturer's data for the installation of the shower and the location to where you want to fit the 20A switch.
not a lot of info in the post.
not a lot of info in the post.
Single or double socket? Normal practice is to is to use 2.5mm.
What is the power of the shower in kW / amps?
Not good practice to mix cable sizes on a circuit, On a 32A ring or 20A radial circuit, all cables must be rated at 20A or more. 1.5mm² T&E cable is rated at 20 A clipped direct, so would just scrape by provided the cable was not in any sort of conduit or insulation. Better to use 2.5mm² cable.
A 20A switch for isoilating a shower is almost certainly massively inadequate. Even a lowly 7.5kW shower will draw 32 A at 240V. What do the instructions say? I bet 20p they specify a 45A double pole isolator.
A 20A switch for isoilating a shower is almost certainly massively inadequate. Even a lowly 7.5kW shower will draw 32 A at 240V. What do the instructions say? I bet 20p they specify a 45A double pole isolator.
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starspark
So your saying 1.5mm is ok to take directly off a socket as a spur??
littleleaks said:
In a word, no!
I think perhaps that you misunderstand the purpose of fuses. A fuse protects the cable that lies downstream or, to put it another way, a cable should be big enough for the fuse that protects it. The load on the end is not relevant. If the existing socket is on a ring, it will most likely be protected by a 30 amp fuse or 32 amp breaker and it will be wired with 2.5mm cable.There is actually an inconsistency here because that size of cable is not rated at 32 amps.
It's one of the few situations where fuses protect the cable lying upstream. (The other common one is the cable leading into your house from the street.) The assumption is that you can only draw a maximum of 26 amps from a double socket - and even this is unlikely to happen - so 20 amp rated cable is acceptable.and also said:
That's highly unlikely. I've never seen an electric shower that took less than 30 amps and that was a small one (7kW). Many take more than this.
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elrobbo82
starspark
not good practice i would install an fcu. but in theory if you have a 5A socket outlet you are restricted to the load that can be attached. but there are no load sizes hence my very vague response.
not good practice i would install an fcu. but in theory if you have a 5A socket outlet you are restricted to the load that can be attached. but there are no load sizes hence my very vague response.
What about a single socket that is designed for a 13amp plug?
It's not really good practice, and not something I would personally do, but there is nothing to prevent you taking a spur in 1.5mm² cable providing the installation method means the CCC isn't reduced and the run is short enough to meet VD and EFLI requirements.
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elrobbo82
technically starspark yes as other people have confirmed. who's competency is in question now?
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starspark
erm elrobbo i didnt say it was or wasnt i was asking you a question for once as i am tired of answering all your trivial ones. But unlike yourself i wont have the mods erase all posts when you look silly on your posts.
And be assured you certainly couldnt bring my competency into question.
And be assured you certainly couldnt bring my competency into question.
Ok so 2.5mm is it for the spur, anyoe want 25meters of 1.5mm ) The shower will be between 9 and 10kw, customer has not yet bought it. The current iso switch is upstairs but the shower is downstairs so I am wanting to put a new iso in. If I buy the highest rated one then I ought have no problems?
) The shower will be between 9 and 10kw, customer has not yet bought it. The current iso switch is upstairs but the shower is downstairs so I am wanting to put a new iso in. If I buy the highest rated one then I ought have no problems?Ok so 2.5mm is it for the spur, anyoe want 25meters of 1.5mm
Are you sure you should be completing this work? You are asking some very basic fundamental questions.
Does the customer know you are seeking advice to do the job from a DIY forum?
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starspark
Beat ya to it!
But you couldn't put a 5A socket on a circuit protected at 32A anyway, so you'd deffo need a FCU.
AIUI ring circuits must be in >2.5mm cable and that includes unfused spurs. Except for MICC of course.
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