Correct cable for electric shower

sparky40

I have recently bought an aqualisa quartz electric 10.5kw shower, and was wondering what is the correct cable to use to wire it up. Some folk have told us that 6mm will do and others have advised that it would take 10mm 6242Y.

I know this wire is expensive and was hoping for some advice before I shell out this expense and then find out it is the wrong type!!!

Thanks in advance.

sheslookinhot

The correct size is 10mm. But you should really know what your doing in installing a shower. It sounds like you should get in a professional to do the work. This type of work may need to be certified. Have you consulted buiklding regulations ?

sparky40

I'm getting a spark in to do the work but my brother in law has given me a length of 6mm cable, and i wanted to double check first!

plumb1_2

Yep you need 10mm cable

sheslookinhot

Good to hear, your better doing it right. Using 6 mm cable for any length of time with that shower is likely to make your central heating redundant.

baldelectrician

sheslookinhot wrote: »

The correct size is 10mm. But you should really know what your doing in installing a shower. It sounds like you should get in a professional to do the work. This type of work may need to be certified. Have you consulted buiklding regulations ?

The correct size may even be 16mm (or higher :eek:)- I had to use 16mm in a flat recently as 10mm would have been too small on a 10kW shower (cables have limiting factors that need taking into account when installing)

Limiting factors may include (amongst other things)

• ambient temperature (above 30 Centigrade)
• Grouping of cables - bunching up for another word
• Cables passing through insulation
• Cables surrounded by insulation
• Length of run
• Load of circuit / size of MCB

matbe

baldelectrician wrote: »

The correct size may even be 16mm (or higher :eek:)- I had to use 16mm in a flat recently as 10mm would have been too small on a 10kW shower (cables have limiting factors that need taking into account when installing)


Limiting factors may include (amongst other things)

• ambient temperature (above 30 Centigrade)
• Grouping of cables - bunching up for another word
• Cables passing through insulation
• Cables surrounded by insulation
• Length of run
• Load of circuit / size of MCB

Come on more info required here this must have been an extreme install.
more facts please.

Alias_Omega

I (Current ) = P (Power) / V (Voltage)

Based on 230~235volts, your looking at approx 45amps.

Therefore, i would go with 10mm T&E on a 45amp MCB (on RCD side) / RCBO.

If the cable run is long, then you may need to consider a smaller shower / bigger cable.

10mm T&E can be bought at about 85p a mtr off the roll if needed.

sparky40

I havent seen it that cheap where can you get it for 85pence pm, cheapest I have seen it is 1.47 pm. I have calculated it to be about 18-20m from the meter box to the bathroom where the shower is. I am going up the wall into the bedroom and under the floorboards to the bathroom.

andrew-b

There's a useful calculator here that gives a rough idea: http://www.tlc-direct.co.uk/Technical/Charts/VoltageDrop.html

...but as your asking here i'd suggest that your better off getting an electrician to worry about this for you - particularly as it's very likely part p notifiable work. If your trying to save costs by running the cable yourself and getting a spark in to connect up i'd say your best off asking the electrician whose going to do the job.

You will also need to be sure that the consumer unit and main fuse are capable of supporting 10.5kW at the same time as other electrical equipment around the house - when i looked into electric showers myself i soon realised it would require a bigger main fuse, new meter tails and new (or second) consumer unit so it just wasn't financially viable for us.

Andy

baldelectrician

matbe wrote: »

Come on more info required here this must have been an extreme install.
more facts please.

It was a short run above a loft with >100mm insulation (the cable calc on TLC shows 16mm!)

Loft insulation is the killer where cable sizes go up to compensate