How to wire an rcd according to regulations?

[Spudnik]

An RCD will offer you earth leakage protection.An RCBO will offer you combined RCD/MCB protection which will include overcurrent

I know, but why do RCBO's need them for the RCD function(?) yet RCD's dont?

 

[Mac]

I know, but why do RCBO's need them for the RCD function(?) yet RCD's dont?

If you don't have an RCD protected board,where the customer won't pay for a board change or something like that.You could change the main switch to 30mA but that would take everything out.Only other option is to install an RCBO on that designated circuit

 

[isitintheregs]

If you don't have an RCD protected board,where the customer won't pay for a board change or something like that.You could change the main switch to 30mA but that would take everything out.Only other option is to install an RCBO on that designated circuit

How does one carry out safe isolation if you change the main switch for an rcd. Cutting the main incoming seal and pulling the fuse appears to be the only way, if so is this acceptable practice?

 

[spark1]

I know, but why do RCBO's need them for the RCD function(?) yet RCD's dont?

Jason I remember reading somewhere that RCBOs require the earth connection as a reference point and without them they would fail to respond to lost neutrals or n-e faults....dont know is this is exactly correct and I must say its a test I have not tried out myself to confirm it


spark1

 

[Spudnik]

Jason I remember reading somewhere that RCBOs require the earth connection as a reference point and without them they would fail to respond to lost neutrals or n-e faults....dont know is this is exactly correct and I must say its a test I have not tried out myself to confirm it


spark1

Ah yes you could be right there, as most RCBO's are only single pole and so therefore, without the flylead, the neutral could go to earth with the RCBO detecting it.

How does one carry out safe isolation if you change the main switch for an rcd. Cutting the main incoming seal and pulling the fuse appears to be the only way, if so is this acceptable practice?

Most RCD's are double pole, so there is your safe isolation.

However, the use of an RCD as a main switch is not a good idea with regards to nuisance tripping.

Hence the dual RCD boards.

 

[spark1]

Yes Jason, there is also the problem when using single pole RCBOs that when a N-E fault is detected and the device trips off it only isolates the Phase conductor and leaves the original N-E fault still in circuit....possible problem in TT systems....


spark1

 

[sparks1234]

Hagers do have a flylead, fitted some only yesterday. Also I would be interested how much are people paying for the Hager RCBO for a consumer unit and how much are they paying for an RCBO for a 3-phase board

 

[Spudnik]

Hagers do have a flylead, fitted some only yesterday. Also I would be interested how much are people paying for the Hager RCBO for a consumer unit and how much are they paying for an RCBO for a 3-phase board

Not at home at the moment but will have a look later.

I have just done a few Hager DB's and CU's.

From memory, the DB RCBO's are around £20 on top of the standard ones!!!

 

[sparks1234]

Well, I have just taken my wholesaler to task on this, I am now paying 20 quid for the ADN rcbo units for consumer units and 24 quid for the AD for dis boards, its all because of the length of the neutral lead, quite bizarly the neutral lead still didn't reach

Should add really, I got the bill through for the dis board ones (AD) and they were £51-00, they took it up with Hager and got the discounts sorted out.

 

[Spudnik]

I am surprised the neutral lead did not reach as the neutral bars are labelled bottom to top along with the DB (if you start nearest the main switch) so the distance should stay the same as you go up the bus bar.

I have just done a 16 way and didnt have any probs.

 

[sparks1234]

Ah, this was an older board and had earth on the left and neutral on the right

 

[Spudnik]

Ah, this was an older board and had earth on the left and neutral on the right

Ah fair enough.

These RCBO's are doing my head in tho.

Its near enough impossible to keep the inside of DB tidy with all the earth and neutral fly leads trailing everywhere.

Do you cut yours??

 

[sparks1234]

I try not to, you never know when you may take them out or move them around. I think you commented on a thread I had going a while ago about RCD's on commercial premesis. I again asked the ECA this week about using them in offices etc, they state that they should not be used on either lighting or power circuits unless it is a tea point or cleaners sockets etc as it is a controlled enviroment and anything hung on walls etc should not be done by office staff

 

[Spudnik]

Hmm thats very interesting they said that, however, this shop/showroom i have just installed, does have 2 lady members of staff plus the owner and he is a hands on kind of person.

How would that stand then??

He is certainly one for putting things on walls.

 

[sparks1234]

Yep I must admit, showrooms, shops I would put RCD protection in, I think what they are also saying is that in an office things tend to be plugged in and left there, I did also question them about sockets chased into walls and he came up with the same answer..no RCD
Just going off the subject a bit, if you are installing floor boxes and client doesn't want to pay for some lovely electrak, what method of wiring do you use?

Should have said it was a raised access floor