mixed circuits

[growler]

Im currently in the process of 1st fixing a load of flats for a company as a subby. ive been told to do a kitchen appliance ring on a grid switch and also a radial for a microwave off the same grid switch. Also there is a heat recovery system and they want the boost switches as part of the light switches. Usually i would do a seperate spur for a microwave and have the boost switches seperate next to the light switches. Im just concerned it wont be obvious that there is actually two seperate circuits in the grid / light switches. Seems like bad practice to me !
Your thoughts would be appreciated !

 

[Guitarist]

Then i apologise for my blunt post.
I just assumed that experienced sparks such as yourself would not be fazed by a relatively minor issue.

biff, after 15 odd years in industry I have seen things that would make a lot of domestic sparks' hair curl, so no, 2 supplies in 1 box does not faze me.
My post was simply to point out that it is now considered bad practice (however common), and against regs, to have 2 separately isolated supplies in one box unless labelled as such. I offered a solution which would work well, whilst maintaining upstairs and downstairs lighting on their own circuits. The other obvious solution is the one stu suggested.

 

[alarm man]

Better that than a funeral though mate?

hence my ocd,were always told test,test,test,but sometimes you test again to be sure,if know one said it youd do your test and crack on,but these days co's have to cover their backs,so if you tested 9 times they say do 10 to make sure..

 

[Guitarist]

as said by biff safe isolation no prob !
its ok to have 400v at a switch so can see no prob with 230v
which book is that i dont remember reading that one! lol
i would say its common practice not bad practice

It's called BS7671:2008

 

[sedgy34]

Q, is a 12 gang switch in a large open plan office bad practise you would have more than 2 circuits in that baby

 

[Mark_Burgess]

Im currently in the process of 1st fixing a load of flats for a company as a subby. ive been told to do a kitchen appliance ring on a grid switch and also a radial for a microwave off the same grid switch. Also there is a heat recovery system and they want the boost switches as part of the light switches. Usually i would do a seperate spur for a microwave and have the boost switches seperate next to the light switches. Im just concerned it wont be obvious that there is actually two seperate circuits in the grid / light switches. Seems like bad practice to me !
Your thoughts would be appreciated !

As the Consumer unit will be labelled, the EIC will be filled out, and the switches could be labelled also, and use a numbered cable marker at the switch point and consumer unit, I can't see there being much of a problem.
Any spark at a later date should carry out safe isolation, if they don't then thats their problem if they get a belt from it.

 

[Guest55]

It's called BS7671:2008

You sure its not BS7671:2008 AMD1 2011 ?
;-)

 

[Guitarist]

You sure its not BS7671:2008 AMD1 2011 ?
;-)

I stand corrected. :icon14:

 

[Guest55]

Sedgy does raise a good point though Guitarist.
Its common practice to have multi switch feeds in commercial installs , impossible to light up say an open plan office with just 1 circuit at a grid switch.

 

[Ponty Massive]

But to answer your question , well you cant can you ?
As its only a house with only 2 lighting circuits its not going to be that difficult to isolate both so i wouldnt lose any sleep over it.

And as to the claim of "bad practice" , i call bullcrap on that.
If you follow proper safe isolation proceedures then it doesnt matter if theres 4 circuits in the switch box , there will be no risk.
Folk just dont like being faced with something out of the norm.

Although i must say that i never said i would do it this way nor advised anyone to put 2 circuits in 1 box did i ?

Its common practice to have multi switch feeds in commercial installs , impossible to light up say an open plan office with just 1 circuit at a grid switch.

Man I'm all over the place now.....So do you agree or not?


I find it difficult to be told on a new domestic installation, where ground and 1st floor lights are on seperate cct's, it's bad practice to put both switch wires into one back box.

So on a new build / rewire, should put two seperate 1-gang switches in? Different phases 415v then i'm with you, upstairs down stairs lights, non-sense.

If your stupid enough to remove the switch and start disconnecting without testing, then you deserve to dance the 240 tango!

 

[Guitarist]

Sedgy does raise a good point though Guitarist.
Its common practice to have multi switch feeds in commercial installs , impossible to light up say an open plan office with just 1 circuit at a grid switch.

Quite agree biff. I think the main difference here is that in a commercial/industrial environment, the electrics will only be touched by qualified electricians (on the whole), whereas in domestic there is quite a lot of "looking after the stupid" going on. It's quite common for Mr Smith to take his light switch off and fit a new plate, whereas how many factory workers would even touch the electrics?
Great Britain (unfortunately in my opinion) has all its H&S set up to "prevent" people from doing stupid things such as falling down holes, whereas most Nations are set up to "warn" people, hence my stance on what is considered by the regs as "bad practice" (however common).
Please remember, I have never said that I agree with all the regs, but I do try to provide a professional opinion on how I interpret them. I wish certain people would understand this and stop giving me abuse.

 

[growler]

The op is a subby and should either do as told and label it or just ask his superior the question the company must 1st fix like this and label the back of the switch, or the customer doesn't want switches next to switches

This is my problem. I dont like the way ive been asked to wire these flats but i dont want to go over the supervisors head.

 

[growler]

Growler I think you have mis understood what you have been asked to do, I've just re read your issue and I don't think your being asked to put 2 circuits in 1 grid box. "I maybe wrong here"

The grid is on the kitchen ring. But it also had a 16A radial from the board to the grid sw then to the microwave.

 

[sedgy34]

Microwave seperate 20amp double pole switch next to grid switch

 

[growler]

Microwave seperate 20amp double pole switch next to grid switch

yeah thats what id normally do.

 

[Guest55]

Man I'm all over the place now.....So do you agree or not?

Well its probably not a good idea in a domestic installation but a design neccesity in commercial environment is the best way i can comment on this.

 

[sedgy34]

Better still, do whatever as it should only be us guys opening that grid switch at a later date I'm also assuming the switches will be engraved and a label inside so that's ok with me. I wouldn't do it but if I was called to it later down the line it Being labelled etc would give me some inclin

 

[mackers]

the only people who read the regs are on the whole are electricians and the regs are open to interpration by each individual
they will never been able to cater for idiots! any good electrician would presume theres a chance of more than 1 circuit at a 2g sw and would test, diy darrens will never be stopped untill electricity is seen in the same light as gas and anyone proved to have worked on it without the correct certs etc would be fined or jailed! or sent to the electric chair along with there first born!!!!!