What would be the best to do ?

[Power Ball]

Can you guys give me some advise please, I went to look at a job yesterday and basically it is a small cottage with a 6 way Wylex re wireable cu on econ seven for night storage heters and a 6 way Wylex to control his 2x light radials 2x sockets rings 1x cooker 1x immersion heater.

Both are fed from a henley block to split the incoming tails

I have been asked to upgrade as the guy is looking to let the ptoperty.

Room on the board is at a premium.

Should I leave the econ seven cu alone and change the domestic cu ?

As I only have 10" room for new cu I can only think to use either 10" enclosure with main switch and 6 RCBO's or would it be ok to use a 10" enclosure with a RCD as the main isolating swich with 6 MCB's ( would this be going back to 16th edittion) + all mcb's would be coverd by the same RCD

Earthing is supplied by a TT rod

Is there a more effective way to do this and keep within the regs...

Any ideas would be greatly appreciated

Many thanks

Chas

 

[Evans Electric]

That sounds like a 14th edition install not 16th TBH.

I think you need to do a full upgrade, specially as its a TT .

Scrap both boards and start again . Just have to create room.

If its being let out a PIR will be asked for and theres not an RCD in sight .

Rod needs to be inspected.

 

[Zeespark]

Does your customer still want to keep the Econ?

You can't use SP RCBO's on TT, DP only, which wouldn't help you much in a small space as each RCBO takes up 2 ways each.

AndyGuinness

 

[Sidewinder]

Does your customer still want to keep the Econ?You can't use SP RCBO's on TT, DP only, which wouldn't help you much in a small space as each RCBO takes up 2 ways each.

AndyGuinness

Zee,

I disagree, I have trawled the regs and cannot find anything that says you must use DP RCBO on TT.

I have not updated this to the Green book, but, under Red it could be said to be OK.

IIRC, myself & M107 put together a case in a thread.

Steps disagreed, and it hinged on one reg, not sure if this reg has changed or not!

 

[kme]

+1

I`d rip it out & start from scratch, TBH - silk purses & sows ears........?

 

[Zeespark]

Sidey, how can you get 30mA protection on N-E if you have a SP RCBO? Not trying to cause arguments, just wondered is all.

AndyGuinness

 

[ProDave]

Sidey, how can you get 30mA protection on N-E if you have a SP RCBO? Not trying to cause arguments, just wondered is all.AndyGuinness

I think all RCBO's sense the imbalance between L and N, which of course is why the N passes through the RCBO. So a N-E fault would be detected.

But when a fault is detected, a SP RCBO only disconnects the L as it's only a single pole SWITCH contact.

 

[Power Ball]

Does your customer still want to keep the Econ?You can't use SP RCBO's on TT, DP only, which wouldn't help you much in a small space as each RCBO takes up 2 ways each.

AndyGuinness

Yes my customer still wants to keep his econ seven so would I be better to pull both out and put his night storage on unpretected 100a main switch and his domestic sockets/lights on RCD in the same enclosure ?

Chas

 

[sellers]

is there a 100mA RCD up front on this? As a matter of safety you'll need one if your leaving the econ board, should be one there in the first place, and if there is one, does it work?? Probably never been tested since it was installed.

 

[Power Ball]

is there a 100mA RCD up front on this? As a matter of safety you'll need one if your leaving the econ board, should be one there in the first place, and if there is one, does it work?? Probably never been tested since it was installed.

Hi yes there is a 100mA RCD up front and it did work ok manual push test.

So would you leave that in to cover the econ board and just change the domestic board. Would it be a better if I pulled both boards out and put in a 12 way with all econ mcb on 1 RCD and all domestic sockets/lights on the second RCD

Chas

 

[Evans Electric]

I'm losing you on this Power Ball .

What RCD is upfront ?

Are you saying you are leaving the rewirable boards in?

 

[Power Ball]

I'm losing you on this Power Ball .What RCD is upfront ?

Are you saying you are leaving the rewirable boards in?

Sorry Deke

At present there is a 100mA RCD up front of 2 wylex rewireable boards 1 board has 6 ways to supply eco seven stoage heaters and the 2nd board supplies his domestic sockets/lights cooker and shower

I am looking for the best way to upgrade, I was not sure if I could put all circuits in to one 12way cu ie eco seven covered by 1st RCD and domestic covered by 2nd RCD or still have two seperate onesI just need advice on which would be the best way forwards.

Hope that has made it a bit more clear for me to get the right advise.

Thanks

Chas

 

[steptoe]

Hi yes there is a 100mA RCD up front and it did work ok manual push test.

does no-one learn how to test RCDs anymore? headbang

that is the LAST test you carry out, most deffo not the first!

pushing the button doesnt prove the RCD works, merely that it separates, it might well work under test now that you have forced it apart.

Id replace the 100mA upfront and fit 2 new boards, BTW, if you are using SP RCBOs which,( IMHO ) dont comply anyway, how are you going to negate the effects of daisychaining a N-E fault?

you could possibly fit a HI-INT board and reconfigure the connections inside to save some room instead of fitting 2 boards.

 

[Doc Hudson]

Hi yes there is a 100mA RCD up front and it did work ok manual push test. So would you leave that in to cover the econ board and just change the domestic board. Would it be a better if I pulled both boards out and put in a 12 way with all econ mcb on 1 RCD and all domestic sockets/lights on the second RCD

Chas

The first check you should have done on the RCD was an electrical test with an approved RCD tested. Not the test button, that would have given a better indication if it was susceptible to sticking and increased operating times. But at least it did operate, which is better than completely jammed.

Doc H.

---------- Post Auto-Merged at 22:53 ---------- Previous post was made at 22:51 ----------

Ah, steptoe read my mind before I could post. Or I forgot to read to the end of the thread, Probably the later!

Doc H.

 

[PC Electrics]

Wylex used to do a 24hr/E7 combo board. It had two main switches. One controled a dual RCD side and the other an unprotected side where you could use RCBOs for the heaters. I used a couple of these in all electric properties - they were rather good. OK the cost goes up somewhat with using RCBOs for the heaters, but that's really the only way to go (if you put them all on one RCD it only takes one faulty element and the owner wakes up one freezing winter morn to no heat or hot water).

You could use a Hager 15 way hi int board, buy an extra main switch and a split load kit and reconfigure it all into one enclosure.

 

[Power Ball]

Wylex used to do a 24hr/E7 combo board. It had two main switches. One controled a dual RCD side and the other an unprotected side where you could use RCBOs for the heaters. I used a couple of these in all electric properties - they were rather good. OK the cost goes up somewhat with using RCBOs for the heaters, but that's really the only way to go (if you put them all on one RCD it only takes one faulty element and the owner wakes up one freezing winter morn to no heat or hot water).You could use a Hager 15 way hi int board, buy an extra main switch and a split load kit and reconfigure it all into one enclosure.

Thanks for reply, thats why I was reluctent to put all heaters on 1 RCD thought they would be better on RCBO's and at least only one goes off due to fault

Cheers

Chas

 

[steptoe]

Thanks for reply, thats why I was reluctent to put all heaters on 1 RCD thought they would be better on RCBO's and at least only one goes off due to fault Cheers

Chas

as long as you can prove SP protection is acceptable for TT,

do you understand the differences between SP and DP protection and how it makes a difference from TN and TT systems?

---------- Post Auto-Merged at 23:12 ---------- Previous post was made at 23:11 ----------

at least only one goes off due to fault

not necessarily, N-E could daisychain.

and with SP RCBOs you still dont have adequate protection.

 

[PC Electrics]

I have put upstairs heaters on MCBs. In theory the 4 inch section of cable that comes up behind the skirting forces an RCBO, but in reality what's the risk.....?

And you've still met the requirement of pP: "no less safe"

 

[steptoe]

PC , this is a TT install.

 

[ProDave]

Hi yes there is a 100mA RCD up front and it did work ok manual push test.

does no-one learn how to test RCDs anymore? headbang that is the LAST test you carry out, most deffo not the first!

pushing the button doesnt prove the RCD works, merely that it separates, it might well work under test now that you have forced it apart.

I have to disagree, to some extent.

Every RCD that I have seen, the test button works by inducing an imbalance usually very crudely with a resistor from L on one side of the sense coil to N on the other side.

So if the RCD trips by pressing the test button, it means it has sensed an imballance and the detection circuit has worked and the RCD has tripped.

I have never come across one where the test button "forces" the contacts open (though that doesn't mean that type does not exist)

So I would say pressing the test button and it working is a good start.

Of course that sort of test is no good for us in the real world, as to do a proper test, we need to know how long it takes to trip at different currents, something you cannot tell from pressing the test button, which is why we use RCD testers that apply a known imbalance and measure the trip time.

Now I would hope Power Ball has a proper RCD tester and will take some proper trip measurements of any / all RCD's in the installation. Otherwise he can't sign any certificates to say they are operating correctly.