Double pole isolation

[rainydays]

Hi all i was on a job today, domestic dwelling. TN-C-S supply.

Inside the meter box before the consumer unit i noticed a double pole isolator, however only the line conductor was passing through the isolator.

The isolator was all sealed.

Surely this does not comply with 537.1.4

 

[NozSpark]

Have a look at 537.1.2 mate

 

[rainydays]

I have but it directs you back to 537.1.4

 

[NozSpark]

The notes where it refers you to 537.1.4 are for PEN conductors only,,,,, and as you know we are not allowed to install PEN conductors

 

[steptoe]

BTW, as an aside,

concerning DP isolation on TT, my NICEIC AC assessor was undecided on the matter,

although the main switch 'could' be used, and was acceptable, it may be dubious as to whether it complied under fault conditions if SP RCBOs were used,

he did think that either RCDs or DP RCBOs would be 'good practice' and be deemed more compliant than SP RCBOs and a DP main sw as an isolator.

so there we have it, even the people that like to think they make the rules dont know the answer. :|

 

[Zeespark]

Steps, the biggest reason why alot of electricians in the UK don't fit DP RCBO's is the fact that they take up 2 modules and are a ****** to get a hold of most of the time.

AndyGuinness

 

[steptoe]

Andy i know where you are coming from,

But, that is not a reason enough.

BTW, you can get DP RCBOs that only take up one way.

There doesnt really seem to be a definitive answer on this, hopefully it wont take a fatality for this to occur.

The other thing we talked about was a possible daisy chain reaction taking out all the RCBOs on a N E fault if the resistance was low enough.

 

[Sidewinder]

I am having a cuppa and a mo having just got home from prison.

I am rubbish at trying to multi quote and selectively quote from previous messages.

I don't think I'm gonna be able to write a meaningful post on the other thread again today, however, I would like to make a quick comment here.

Plumber,

Relating to your response in the quote of Steps msg above wrt 537.2.1.1 ^

There would be very few situations where it would not be acceptable to utilise the main switch to isolate a domestic premises, which is IIRC what we are talking about here.

Your direction to this reg is relevant, but, this can be negated in a domestic by just turning the whole thing off!

I did go through the regs recently and post my opinions on another thread as I have a customer who wants to go the RCBO route & I am not happy with SPSN, however, space, cost & availability are issues for DP.

M107 & myself, & Steps all posted, I'm surprised you missed it!

Not saying you are wrong, but if you have a look at our comments then you may be able to add something constructive.

There is a little grey area over this really, though if you go through the regs it is allowed, baring for a few points where they seem to be optional.

Once you move away from domestic mind then there are many other considerations.

As far as the NICEIC AE's go, they are not party to the rule making, mine for example will have his say to the IET and the NICEIC on any proposed changes etc.

I will also have my say to the IET, and possibly the NIC (as an AC), however, I am more highly qualified than he is!

We are both IEng btw.

Can't fault your comments to rainydays.

The only issue as you say would be if some Muppet did not fit a dp isolator within the main install!

 

[Chr!s]

I am having a cuppa and a mo having just got home from prison.I am rubbish at trying to multi quote and selectively quote from previous messages.

I don't think I'm gonna be able to write a meaningful post on the other thread again today, however, I would like to make a quick comment here.

Plumber,

Relating to your response in the quote of Steps msg above wrt 537.2.1.1 ^

There would be very few situations where it would not be acceptable to utilise the main switch to isolate a domestic premises, which is IIRC what we are talking about here.

Agreed, in most instances in a domestic this is not an issue, i did place a quote from the regs in my post "537.2.1.1 Provision may be made for a group of circuits by a common means, if the service conditions allow". This part of the Reg allows the designer to make the risk assessment.

Your direction to this reg is relevant, but, this can be negated in a domestic by just turning the whole thing off!

Not always, and Steps did not state as to whether his predicament was a domestic or commercial, hence why my reply was clear in both instances.

I did go through the regs recently and post my opinions on another thread as I have a customer who wants to go the RCBO route & I am not happy with SPSN, however, space, cost & availability are issues for DP.

M107 & myself, & Steps all posted, I'm surprised you missed it!

Ill see if i can dig it out.

Not saying you are wrong, but if you have a look at our comments then you may be able to add something constructive.

There is a little grey area over this really, though if you go through the regs it is allowed, baring for a few points where they seem to be optional.

Once you move away from domestic mind then there are many other considerations.

As far as the NICEIC AE's go, they are not party to the rule making, mine for example will have his say to the IET and the NICEIC on any proposed changes etc.

I will also have my say to the IET, and possibly the NIC (as an AC), however, I am more highly qualified than he is!

We are both IEng btw.

I often have disagreements with both, head and wall often spring to mind LOL.

Can't fault your comments to rainydays.

The only issue as you say would be if some Muppet did not fit a dp isolator within the main install!

If you know the title of the thread PM me Cheers.

 

[Sidewinder]

Plumber,

It is this thread.

http://www.talk.electricianforum.co.uk/your-pictures/14897-todays-work.html

 

[Chr!s]

Plumber,It is this thread.

http://www.talk.electricianforum.co.uk/your-pictures/14897-todays-work.html

Cheers