2 gang switch live when dead

[chiplard]

I disagree, 514.1.1 relates to the operation of switch gear not isolation, 514.11.1, it can be isolated from a sigle device, the main switch.

Having re-read 514.1.1 I would agree with you.

You are right with regards to 514.11.1 but it also states that the location of each isolator shall be identified unless there is no possibility of confusion.

What is the problem with losing both lights over the stairs?

 

[Des 56]

Safe isolation is the major player with this debate
If a person islolates a single mcb and follows safe isolation procedure, he will soon find out that it needs 2 mcbs isolated
So in theory,no danger can exist,if in doubt,a person working on the switch should do as hifly suggests, and switch off the main switch

There is nothing wrong with 2 seperately supplied circuits in one switch box

 

[Deleted member 19807]

What is the problem with losing both lights over the stairs?


314.1

 

[chiplard]

Safe isolation is the major player with this debate
If a person islolates a single mcb and follows safe isolation procedure, he will soon find out that it needs 2 mcbs isolated
So in theory,no danger can exist,if in doubt,a person working on the switch should do as hifly suggests, and switch off the main switch

There is nothing wrong with 2 seperately supplied circuits in one switch box

How would he find out? A sparky with a meter would. But a home owner?

I agree there is nothing wrong with 2 separately supplied circuits in one switch as long as it is identified correctly, as stated in the BRB.

 

[chiplard]

What is the problem with losing both lights over the stairs?


314.1

Would you put every room on its own MCB then?

 

[Des 56]

How would he find out? A sparky with a meter would. But a home owner?

I agree there is nothing wrong with 2 separately supplied circuits in one switch as long as it is identified correctly, as stated in the BRB.

Thats why we get ourselves all trained up and paranoiac
We are supposed to understand safe isolation

If the home owner wants to perform the job,then there is training available,otherwise, his best decision would be to employ that trained person
The regs are not made up in order to allow incompetent work on systems,rather that the systems are safe,they leave the competence issues to others




quote
agree there is nothing wrong with 2 separately supplied circuits in one switch as long as it is identified correctly,

Are you honestly asking to believe that in a domestic situation,if you had a 2-gang switch with up + down circuits present,you would stick a warning label on or at that switch ?

 

[chiplard]

With respect mate and not wanting to get into a war of words can you please explain the wording in 537.2.1.3 to me. It clearly states 'any person' gaining access to live parts.

 

[Deleted member 19807]

Would you put every room on its own MCB then?

As the designer its up to you to decide how to comply with 314.1, personaly in a standard 2 up 2 down i would have, mainswitch,RCD1, cooker, ring up, immersion, lights down, RCD2, ring down, garage,lights up, lights outside, c/heating. if an rcd trips you don't loose power to a whole floor or both lights over the stairs, better still all rcbo' but we must balance cost with function.

 

[Deleted member 19807]

With respect mate and not wanting to get into a war of words can you please explain the wording in 537.2.1.3 to me. It clearly states 'any person' gaining access to live parts.

more then one supply could be 2 incommers, or 1 incommer and a generator or PV panels, supply is not an mcb,

 

[Des 56]

With respect mate and not wanting to get into a war of words
The reply might have come over as cold,if thats so.sorry it was not intended to be so

I dont particu;arly want to argue the case
I will leave the last word to you

I wont get the brb out just yet, later maybe when I can motivate myself

I expect your interpretation of that reg will be different to mine,I have never in many many years seen a warning notice at or near or at the dist board in a domestic installation.telling of the issue

 

[chiplard]

quote
agree there is nothing wrong with 2 separately supplied circuits in one switch as long as it is identified correctly,

Are you honestly asking to believe that in a domestic situation,if you had a 2-gang switch with up + down circuits present,you would stick a warning label on or at that switch ?[/QUOTE]

No i wouldn't as it would look an arse, but i would wire it to avoid such instances. Be it extra work to run circuits up/down stairs or put separate switches in.

We install to meet the regs not just to please the customer. If the customer doesn't want the extra light switch, extra under counter isolator then the work doesn't get done.

 

[Des 56]

Ok I've got the good book out and will firstly bring to your attention
537.2 note: It says blah blah and at the end every source of electrical energy That to me means both poles

A switch in this instance is not an isolator,the function of the isolation is at the distribution board
Because its not an isolator,537.2.1.3 is not relevant

 

[chiplard]

537.2.1.3 is not irrelevant. It states that an enclosure containing live parts will have a notice that warns of the need to isolate said parts from the various supplies. The switch is the enclosure, the isolation of supplies is the DB.

 

[Des 56]

Have a look at the list on page 117
It will show for example that a plug and socket is an isolation device
It shows a 60947-3 is an isolator,all the other switches are not so

The isolation is the distribution board,the switch is not an isolator
There is only one supply for the 2 circuits
That supply will be isolated at the dist board
No notice is required
No clients are having non regulated work done
No 2-gang switches are having notices pinned to them
No un necessary single switches are being mounted

Thats the common practice,the way it has been installed in millions of households

 

[chiplard]

I never stated that the switch was the isolator, the switch is the enclosure.

Please read page 24 ( definition of enclosure ) and 537.2.1.3 again.

Also from page 117, a circuit breaker is a means of isolation, thus if there are 2 MCB's there are 2 supplies.