showers affected by loft insulation ?

[scottg]

6/2.5 for 7.2kw and 10/4 9.6kw
im i reading the onsite guide right if going through
thermal insulation ?
what do they mean buy thermal insulation is this loft insulation ? if so need 16mm for 10.5 kw shower are you having a laugh!
what are you all recommending shower power for 6mm and 10mm
worst case insulation for domestic say 10m run not going to be much more for domestic ples help as reading this is getting confusion as they sate thermal insulation but dont state type of thermal insulation

 

[Softus]

what do they mean buy thermal insulation is this loft insulation ?

Yes.

if so need 16mm for 10.5 kw shower are you having a laugh!

Are you?

what are you all recommending shower power for 6mm and 10mm

10mm² will safely carry 43.0 Amps if insulted - not enough for a 10.5kW shower going at full pelt.

worst case insulation for domestic say 10m run not going to be much more for domestic ples help as reading this is getting confusion as they sate thermal insulation but dont state type of thermal insulation

You could help people to help you, by using punctuation.

 

[llewop]

I always use 10mm for all size off shower. The 16mm you refer to in the onsite guild is the correct calculation for loft insulation above 100mm. You would need 16mm cable for a 10kw shower if it was on all the time but as the shower is only on for a short time (ie 20mins approx ) the cable does not heat up enough to cause a problem so 10mm is enough.

I noticed that same thing when sitting the 17th edition so the guy taking the course had to explain it, and that was his answer.

 

[GaryMo]

10mm² will safely carry 43.0 Amps if insulted - not enough for a 10.5kW shower going at full pelt.

I'm not sure where you've got that figure from but from table 4D5, 10mm is rated at :

Method 100# - 45A if installed above a plasterboard ceiling and covered by thermal insulation not exceeding 100mm.

Method 101# - 36A if installed above a plasterboard ceiling and covered by thermal insulation exceeding 100mm.

 

[GaryMo]

I always use 10mm for all size off shower. The 16mm you refer to in the onsite guild is the correct calculation for loft insulation above 100mm. You would need 16mm cable for a 10kw shower if it was on all the time but as the shower is only on for a short time (ie 20mins approx ) the cable does not heat up enough to cause a problem so 10mm is enough.

OK then....show me, in BS7671:2008 where it says you can ignore current carrying capacity of cables because an electric shower won't be used all day long.

 

[llewop]

Only passing on what we were told on the 17th edition course when we all pointed out that you cannot connect a 16mm cable into a shower. we were told to use commen sense as the shower would not be on all day everyday.

 

[GaryMo]

Have a read of 523.7

 

[Lectrician]

Most large showers will take 16mm easily.

Crabtree shower switches also do happily.

I have used 16mm on a couple of occasions, but predominantly just 10mm as most folk do not want obscenely large showers!

 

[rssteve]

why not just run the cable on top of the insulation in the loft, fix some batten down and clipped it to the batten?

 

[holmslaw]

..

 

[Lectrician]

why not just run the cable on top of the insulation in the loft, fix some batten down and clipped it to the batten?

Stud walls and flat roofs spring to mind