Type of rcbo for circuits

[Frasers]

Hello. I have the following circuits in a static caravan:-
Lights 6 amp
Ring main 32 amp
External sewerage treatment plant 10amp
Electric boiler 40 amp
Electric shower 40 amp

My question is, will type a RCBOS be suitable for all the circuits? Thanks

 

[Murdochcat]

What is your supply as this seems a lot for a static caravan. If this is to update an existing board then you best post a photo of it

 

[Frasers]

Will be a 100 amp supply. New consumer unit. New install. Sparky dealing with the swa cable and earthing etc

 

[Murdochcat]

Here we go …. Get the sparky to specify and install - and test properly

 

[Frasers]

Not helpful.

 

[Murdochcat]

Not helpful.

Well, obviously you don’t know what you need, but claim to be using a sparky so asking them seems the most appropriate solution rather than faceless people on the internet AND bear in mind your sparky will need to connect to the CU don’t you think it’ll make sense?

 

[ericmark]

Looking at the load, one would expect a 100 amp supply, yes type A double pole RCBO's can be used, must be double pole as caravans are not permitted a TN-C-S supply, so would likely be TT supply so RCD's need to be double pole. Electric boiler 40 amp does seem a bit OTT for a caravan, my caravan had less than 10 amp, and the shower in my house is only 32 amp.

A caravan is clearly mobile, calling them static seems wrong, but the main thing is they are made of metal, and so PME is not permitted. So one has to consider both line and neutral as live, so RCD's/RCBO's need to be double pole.

 

[JohnW2]

....., so would likely be TT supply so RCD's need to be double pole.

I presume that the "RCDs" you're referring to are the OP's RCBOs, since virtually all RCCBs are double-pole?

... but why do you make that statement, anyway? In a TT installation there is, strictly speaking, a requirement for any 'isolation' to be DP, but no requirement of which I am aware that the circuit's protective device must be able to provide such isolation, is there?

 

[ericmark]

721.411.1 Where protection by automatic disconnection of supply is used (Section 411), an RCD complying
with BS EN 61008-1 or BS EN 61009-1 interrupting all live conductors shall be provided having the characteristics specified in Regulation 415.1.1, and the wiring system shall include a circuit protective conductor which shall be connected to:

So I read that as with RCBO it would also need to interrupt all live conductors unless changed since 2008?

 

[blup]

Get the wylex rcbos with built in afd and surge protection. John Ward has done an excellent video on the subject on YT recently

 

[ericmark]

The bottom of the picture

shows the problem. Great idea, but silly price. Also, it is single pole switching.

 

[JohnW2]

Get the wylex rcbos with built in afd and surge protection.

.... after speaking with a mortgage broker The OPs five devices would cost best part of £1,000.

John Ward has done an excellent video on the subject on YT recently

That doesn't surprise me. He is an avid promoter of any new (and often expensive) technology - but usually without much (if any) discussion about 'evidence for need' or cost/benefit considerations.

 

[JohnW2]

721.411.1 Where protection by automatic disconnection of supply is used (Section 411), an RCD complying
with BS EN 61008-1 or BS EN 61009-1 interrupting all live conductors shall be provided having the characteristics specified in Regulation 415.1.1, and the wiring system shall include a circuit protective conductor which shall be connected to:
So I read that as with RCBO it would also need to interrupt all live conductors unless changed since 2008?

Thanks. That is now 721.415.1 in the current regs. However, my apologies, since I didn't realise (never have had reason to look!) that there was a specific regulation about this in relation to caravans.

In passing, you often suggest thst the specific regs about electrical installations in caravans exist "because they atre metal". However, are there not caravans in which all of the touchable parts are non-conductive (e.g. fibreglass) and, if so, why do special regs apply to hem?

 

[blup]

.... after speaking with a mortgage broker The OPs five devices would cost best part of £1,000.

Good value

That doesn't surprise me. He is an avid promoter of any new (and often expensive) technology - but usually without much (if any) discussion about 'evidence for need' or cost/benefit considerations.

He does what interests him, but it’s worth remembering that YT isn’t a peer reviewed evidence kind of forum

 

[JohnW2]

Good value

Obviously a matter of opinion!

He does what interests him, but it’s worth remembering that YT isn’t a peer reviewed evidence kind of forum

Indeed. The problem I perceive is that he is (rightly) so respected for his knowledge, communication skills and interest in 'communicating', that his expression of his personal views (often presented such as to make them sound like 'requirements') is probably taken by many to be 'gospel (and evidence-based) fact/truth'.

An awful lot of people were 'taken in' by Richard Dimbleby's "spaghetti bushes"