6mm2 for 8.5 kw shower

[scott g]

can i fitt 8.5 kw shower using 6 mm2 cable 3m from mains board
only thing is its going through loft insulation more than 100mm
would it be ok to use trunking with insulation on top would this effect cable calculations

 

[simopesh]

you are quite right, the red book isnt statutory but i find that by abiding by it on simple things like cable selection i sleep better at night
the fact that the customer is a little old lady with new tiles is irrelevant and not a viable defence when it all goes wrong
each to their own i suppose but i will be sticking with the regs safe in the knowledge my install is 100% correct

My install of 6.0mm twin and earth cable for 8.5Km consumable on a 3 metres run will be 100% safe and secure as well!

 

[WarrenG]

But what is statutory is the requirement to make reasonable provision in the design and installation of electrical installations in order to protect persons operating, maintaining or altering the installations from fire or injury.

If you disregard the current carrying capacities in BS 7671, which are not arbitrary, have you made reasonable provision?


Read 134.1.4 - it's a fundamental principle of BS 7671 that joints will be properly made, and therefore the capacities tabulated in Appendix 4 will be based on the assumption that they have been.



But in what way does it comply with BS 7671?

I see the DIYer Banallsheds is starting to create arguements on this forum also.

Why are you looking to comment on a document that you don't consider to be relevant (BS7671) and more importantly why worry about an EIC when you have clearly stated on other forums that its not needed?

It appears to me that you seem to visit alot of the forums to cause problems with the members for your own kicks. Why bother?

 

[flukey]

simopesh,
i think you are missing the point here.
6mm doesnt meet the requirements of bs7671 which we all work to.
why would you want to install 6mm when you can install the correct 10mm and charge the correct amount for the job too.
the fact that the customer is old and has new tiles has no bearing on us as electricians to feel that because she doesnt want the decor damaged we must bend the rules.
you are quite right in saying that your way will work and i dont dispute that but what will your defence be if it did all go wrong??
as i said each to their own but i feel by keeping to the regs i will always have a clear conscience should the unthinkable happen

 

[coxy]

Hi Guys,
Read all the comments,where as i do feel that bs7671 does go over the top, i have just spent £280 on 17th edition course £100 on books,£450 to renew nic.I will stick to the regs as i have to and anyone else doing electrical instrallation work should do so as well.Its the only way to try to get standards up.It amazes me that for a few pounds more people compromise safety.Why is it our industry allows this i thought part p would sort it out,but it has not !!!

 

[flukey]

well said coxy.
i think you will find most electricians do adhere to the regs, that is after all what they are there for.
like you say theres no point paying out on latest edition courses if you dont intend to use the book properly.

 

[coxy]

Hi Flukey,
You may be right but the real problem is people walking into b&q seeing on a big board how to connect lighting circuits etc.They do not explain the regulations to these people,then when you try to do a proper install and then mention the price you always get funny looks !!! one guy recently called me in because his kitchen install was a complete balls up,said if i could first fix for him could he second fix to save money !!! Would he say that to a heating engineer - pipes are in, i will fit boiler - no.Most sparkys have spent years doing a good job unfortunatly some people still do not understand how skillfull you sometimes have to be,and knowledge we have to learn.Thats it moan over.!!

 

[sparkyork]

just to have me two pennies worth, i wouldnt even contemplate putting 8.5kw shower on a 6mm, the regs may not be statutory but when the **** hits the fan the court is gonna ask if it was done to current regs, your reply would be no sir, then its see ya later enjoy getting bent over in jail!

7.2kw is all i would put on a 6mm, be safe, keeo others safe and dont increase your chances of going to jail, is it really worth it???

 

[scott g]

has anyone had to install 16mm for shower ref 101
10.5kw shower

 

[flukey]

HI SCOTT,
DEPENDING ON THE CONDITIONS THIS IS VERY POSSIBLE. I KNOW IT SOUNDS MAD NEEDING A 16mm TO RUN A SHOWER AND THE CONNECTIONS WILL BE A NIGHTMARE, BUT IF THE CALCULATIONS TELL YOU THAT IS THE CASE THEN SO BE IT. IN THIS CASE YOU HAVE TO LOOK AT YOUR INSTALLATION METHOD AND SEE IF RE ROUTING IS MORE PRACTICAL TO KEEP THE CABLE TO A SENSIBLE SIZE. ONCE AGAIN DO THE SUMS, REFER TO THE REGS AND YOU CANT GO WRONG

 

[KFORDHUNTER]

I to work to current regs, have done my updated 17th course, registered with niceic as domestic installer, have all relevant insurances etc etc.

However i think a point has been missed here, you can put whatever shower you want on a 6mmt+e, just back it up with a 32a mcb, then when it surpasses this amount it will take the breaker out, cable safe.

The real issue is whether or not we want to do the job properly or not. for those that do don't bother arguing with those that don't. They are not going to change their minds and all they will do is hoover up the work we refuse to do.

I sometimes wonder who the real fools are!!!!!!

 

[flukey]

Thats a very relevant opinion.
Not sure i would want to keep getting calls from a customer though when their breaker keeps tripping when i could have installed the job correctly in the first place.
If my workload gets that low that i need to consider competing with sparks that use inferior equipment then i will review my policy at that time.
Until that day arrives i for one will carry on installing every job under the scope of the regs as they are intended

 

[coxy]

When installing any cables now make sure you stay clear of insulation.If needed suspend cables in loft on cable tray then drop down,yes ridicilous but have you ever been in a loft in the middle of summer ????
The regs are there to make sure of a proper installation - simple !!
Yes they are over the top, as i said before but the more regs the better as hopefully it will stop the cowboy sparks !!!

Hi, on what kfordhunter said - think ! when would the 32amp mcb trip on overload ??
Look at the time/current tables - you may be surprised !!! to see how much it could take therefore the cable is as well !!

 

[simopesh]

Hi Guys,
Read all the comments,where as i do feel that bs7671 does go over the top, i have just spent £280 on 17th edition course £100 on books,£450 to renew nic.I will stick to the regs as i have to and anyone else doing electrical instrallation work should do so as well.Its the only way to try to get standards up.It amazes me that for a few pounds more people compromise safety.Why is it our industry allows this i thought part p would sort it out,but it has not !!!

Compulsory “safety” does not come from cable size, however, it does come by adding an additional safety (in this case absolutely compulsory) called Residual Current Device!

When installing any cables now make sure you stay clear of insulation.If needed suspend cables in loft on cable tray then drop down,yes ridicilous but have you ever been in a loft in the middle of summer ????
The regs are there to make sure of a proper installation - simple !!
Yes they are over the top, as i said before but the more regs the better as hopefully it will stop the cowboy sparks !!!

Hi, on what kfordhunter said - think ! when would the 32amp mcb trip on overload ??
Look at the time/current tables - you may be surprised !!! to see how much it could take therefore the cable is as well !!

 

[WarrenG]

Here is a quick cable sizing chart for standard circuits.

There is a limit on the length of the shower circuits though.

http://i421.photobucket.com/albums/pp295/WarrenG_017/CableSizeStandardDomesticCircuits.jpg

Hope it helps

Warren

 

[simopesh]

simopesh,
i think you are missing the point here.
6mm doesnt meet the requirements of bs7671 which we all work to.
why would you want to install 6mm when you can install the correct 10mm and charge the correct amount for the job too.
the fact that the customer is old and has new tiles has no bearing on us as electricians to feel that because she doesnt want the decor damaged we must bend the rules.
you are quite right in saying that your way will work and i dont dispute that but what will your defence be if it did all go wrong??
as i said each to their own but i feel by keeping to the regs i will always have a clear conscience should the unthinkable happen

I do know what I’m talking about. Float of electrons and multi-core cable are laws of physics that I can talk on a much higher level.
What will happen if you install a shower with 10.0mm cable with loose connections? I’m absolutely shore that you know the answer.
In accordance with the current 17th edition the supply tails from meter to board are bound to be 25.0mm double isolated tales. Ok, but how does EDF or the rest of the suppliers comply with the above? Well, I’m afraid to say but they don’t. Some of the domestic households are with 10.0mm main supply piro cable with 4-6 storage heaters, immersion heaters (Low and Normal), electric cocker shower and more. Did you ever ask yourself how do the mains last when people override the tele-switch and everything is pushed to its limits? Believe me it does last!
I know by pure calculations that cable current capacity is largely downgraded for safety; however, with the current technologies its safety issues are unnecessarily exaggerated!
Regards