main isolator switch

[sprottp]

Gents,

Looking at an install which will include two new circuits, one for lights and another for a ring main. There is no space on existing 16th edition board and customer does not want a new 17th edition board, there is no double pole isolator before it.I am planning on Henley blocking the supply and taking a live and neutral to a new RCD 2 way unit. What's puzzling me is... As there is a requirement to have a main switch for isolation rather than using an RCD main switch as the isolator, would I install a double pole isolator external to the rcd unit to meet regs? Already explored ideas of RCBOs with a standard main switch 2 way unit but clients costs are the issue. Thanks

 

[GLENNSPARK]

use a DP iso with RCBOs in that sub board

 

[sprottp]

Thanks Glen, I suggested that to the client but was told no due to the price of RCBOs

 

[GLENNSPARK]

Thanks Glen, I suggested that to the client but was told no due to the price of RCBOs

BG garage board....
british general RCBOs are about 15 quid each

 

[gazj82]

If your being forced to cut corners to keep costs down then it's time to walk away imho. I must admit not being allowed to use a RCD main switch as a main switch is new news to me. I guess you never stop learning

 

[Des 56]

Why do you want a main switch for isolation instead of using the RCD in the board

There is possibly more argument for a single isolator for both installations, albeit not necessarilly required

 

[GLENNSPARK]

If your being forced to cut corners to keep costs down then it's time to walk away imho. I must admit not being allowed to use a RCD main switch as a main switch is new news to me. I guess you never stop learning

to me as well for a sub board...

 

[amo]

Nothing wrong with having an rcd as the main point of isolation in the sub-board. Which requirement requires a main switch instead of an rcd? Just curious...

 

[telectrix]

RCDas main switch in your new board is fine, but fit a 100A D/P isolator before the henleys ( installation should have a single point of isolation ).

 

[gazj82]

RCDas main switch in your new board is fine, but fit a 100A D/P isolator before the henleys ( installation should have a single point of isolation ).

I must admit I even thought two main switches was acceptable if very clearly marked that there was more than one main switch. Obviously avoid this at all costs in the first place.

 

[GLENNSPARK]

I must admit I even thought two main switches was acceptable if very clearly marked that there was more than one main switch. Obviously avoid this at all costs in the first place.

you`v got to look at it as an installation intended to be used by unskilled/uninstructed person/s not under supervision n all that lot....
so a single point of isolation makes common sense...doesn`t it...

 

[gazj82]

Oh yeah, totally agree. Only place I have ever seen it was in a Secondary school on a condition report done by someone else.

We accepted clearly laballing at each main switch that another main switch needed to be switched off for total isolation in a nice tref label. I would never install anything this way to boot. I definitely wouldn't do it in a domestic property.

 

[telectrix]

you`v got to look at it as an installation intended to be used by unskilled/uninstructed person/s not under supervision n all that lot....
so a single point of isolation makes common sense...doesn`t it...

what a waste of words when a simple "muppet" would do

 

[GLENNSPARK]

but its not like me to be rude tel....

 

[telectrix]

jeez. just nearly choked on my ale. was just taking a swig when i read that.

 

[GLENNSPARK]

jeez. just nearly choked on my ale. was just taking a swig when i read that.

what?....
whats wrong?

 

[davethsparky]

Another way to do it if you don't have any spares / only one spare in the existing board is take a supply from an MCB in the existing board to feed your new board and if necessary move a circuit from the existing board into your new board. Not always possible or practical depending on the condition of the old board and circuits.
Advantage of doing this is it all remains on the existing mainswitch and you don't have to pee about with putting henley blocks into the tails which you obviously can't isolate because nobody can break the seals (nudge nudge wink wink etc etc)