RCB or RCBO in a Distribution Board.

[Andy C]

I am getting back into the electrical game after a few years and wondered what peoples thoughts are on the above.

I am happy installing fully RCD protected DBs or Split boards but the use of RCBOs I had never seen. What are the main reasons/advantages/disadvantages for using them? I know they are wired differently within the DB.

Sorry if it seems a daft question.

Thanks for any replies.

 

[Leesparkykent]

RCBO's in the event of a fault will only trip the circuit at fault where as with a dual RCD board or Upfront RCD you could potentially loose half or all you circuits.

 

[Andy C]

RCBO's in the event of a fault will only trip the circuit at fault where as with a dual RCD board or Upfront RCD you could potentially loose half or all you circuits.

Thanks Lees, I get that and was aware, but is it just a general trend towards say rewires now to use RCBOs as standard and move away from split boards or dual RCDs.

Thanks for replying

 

[telectrix]

what he said ^^^^^. the advantage of RCBOs is that a trip will only resultin the loss of the circuit with the fault.

dsadvantages are:
1.cost
2. a trip may be due to either an earth leakage or an overload. a bit more tech. involved than with separate MCB and RCD.

 

[Octopus]

There are RCBO boards that don't cost too much more than Dual RCD boards .... so offer the client the choice.... the pro's of an RCBO board far outweigh the con's of a dual RCD board IMHO.

Also if you have an existing board with, say 4 circuits a dual RCD board doesn't make sense...

 

[westward10]

Also provides complete division of circuits if rcbos are employed, eg. a fault on one circuit, theoretically will not affect another.

 

[telectrix]

just need to get your head around those 30ft long coiled N tails that will not ever sit where you want them to.

 

[hightower]

just need to get your head around those 30ft long coiled N tails that will not ever sit where you want them to.

Chop and ferrule

 

[westward10]

Chop and ferrule

Sounds like a gastropub

 

[sparksburnout]

Just plucking prices off the internet, typical budget board with 2 x RCD and 10 MCB = £66. Same manufacturer 10 x RCBO's alone = £190. Local wholesaler complete board with 2 x RCD plus 8 MCB = £65 plus VAT, similar board with main switch and 8 RCBBO's = £136 plus VAT. It is obvious that, electrically, having discreet devices is better, but does the customer care? Around my way there is almost a "standard" price for a board change, and using RCBO's is going to cut into the profit margin too much, or just mean the job will go elsewhere. I have to say I have had a dual RCD board in my own house for a good few years, never been any problems with associated circuits being taken out on the rare occasion an RCD trips. The "pro's" are fine, but the "cons", in most customers eyes outweigh them by way of not getting the job!

 

[Andy C]

Thanks for the replies guys. When I last did electrics it was all RCD and Split boards. There are so many changes. It looks like I have a steep learning curve over the next few months, but looking forward to getting back to working with my hands.

Testing..... Whats that all about... Thats going to burn up a few of my remaining brain cells...

Thanks again

 

[Octopus]

Testing..... Whats that all about... Thats going to burn up a few of my remaining brain cells...

Best you do some reading or else installing RCD CU's could turn into an unmitigated nightmare for you!

Oh, and the icing on the cake is compliance with Part P - so scheme membership and all that entails!

 

[Andy C]

Best you do some reading or else installing RCD CU's could turn into an unmitigated nightmare for you!

Oh, and the icing on the cake is compliance with Part P - so scheme membership and all that entails!

Thanks Murdoch.
Practically speaking I will be okay as I did a full apprenticeship in the 80s and have all the knowledge and experience in fitting etc. There will be a few bits such as the shortening and crimping of RCBO cables ghat are different.

I am taking the 17th edition and 2394 and 5 in February so hopefully fingers crossed i will obtain passes. I am looking forward to working with my hands again. I am thinking of asking a small contractor if a could shadow them when testing to give me more of an idea, maybe for a cheap day rate for them as an incentive.

As i would be doing mainly domestic I was going to join STROMA

Any ideas or suggestions would be welcome.

 

[westward10]

We don't stick green/yellow wires on every bit of stationary metalwork anymore.

 

[Octopus]

Thanks Murdoch.
Practically speaking I will be okay as I did a full apprenticeship in the 80s and have all the knowledge and experience in fitting etc.

I was referring the testing...... not the fitting.

You know you have to complete an EIC with a CU change?