Which RCD for my consumer unit?

[David2452]

Yes you can use multi strand in a domestic situation, you can also use solid core but you can not use solid core on a boat, what I was trying to do is point out that there are fundamental differences and the correct BSI regs should be followed and that is BS EN ISO 13297:2012 which is designed to make low voltage AC installs aboard boats as safe as possible.

 

[David2452]

Its just that if you buy a bs consumer unit it has the copper bars supplied that to feed single mcbs or rcbos if you make your own board up and a fault developed and caused a fire your insurance could be in question but dave will be best to quote on boats

You don't even really need a consumer unit, many builders comply simply with a hard wired installation (no Bus bar) on DIN rail in an enclosure on boats built to RCD which complies with the correct regulations.
It is very difficult advising on regulations in isolation, regulations designed for people with an understanding of their implications to boot without seeming pedantic but the regs are the regs, Actually though, the regs do not apply to DIY stuff on boats unlike domestic where such DIY works are not allowed in many cases or at least that's what I understand. I do sometimes genuinely worry that a piece of advice which gets misinterpreted and gets a DIYer in difficulty could cause me issues and wonder if I really should.

 

[Norman_E]

mA not mV.

30mA is the most common. For increased personal protection you can use 10mA but are likely to get a lot of spurious trips from noise.
Even some 30mA ones are prone to noise tripping. I've found it worth sticking to good makes like MK rather than electrical factors own brand.

Clearly some are worse than others at noise tripping. I used to have an old domestic consumer unit protected by a single RCD installed in a separate enclosure. It used to trip quite frequently. I changed the setup to a new consumer unit fitted with RCBOs on all circuits, and have never had one of them trip except on test.

 

[nigelmercier]

why should I not be using double pole MCBs?

They would be a real bugger to wire up for a start, and not necessary. Neither is the breaker if you have a DP RCD. The maximum current rating of this is immaterial, it is the trip current that matters: 30mA or lower.

 

[Plevier]

To comply with electrical regs the make of the board rcd and mcbs must be of the same make

I was so surprised by that I did a bit of digging.
Is it actually in the regs? (I don't have access to current edition.)
It is a recommendation by BEAMA which I suspect is more in the commercial interest of their member manufacturers than of safety. http://www.beama.org.uk/download.cfm/docid/FC38F072-57DC-49CA-B6C4A2E412824316
Having had several dreadful Protek RCDs and MCBs pack up in my house and garage I now feel safer with some MK and M-G units in the box anyway.
I wonder why they are made physically compatible and to the same electrical spec?

 

[Seastoke]

Nigel rcd,s give earth leakage protection mcb,s give short circuit protection on mcb,s there are 3 different types on new ones say you put a 6 amp one in you need to decide also which type ,b,c,or d normally b for domestic cis for industrial eg motors or d type eg transformers welders ,it is very rare rcd,s have faulty tripping it is normally a fault on circuits which can be tested ,to answer compatability made to iec or bs speck ,as i spoke before if boat builders do some thing it will have a kite mark or similar if you do it it s an insurance get out in my opinion ,if you have a boat safety cert that may be ok but at sea nothing only hope nothing goes wrong ,note this only my opinion .roy

 

[David2452]

I was so surprised by that I did a bit of digging.
Is it actually in the regs? (I don't have access to current edition.)

I do, and as I said earlier no it is not.

 

[sailorman]

Nigel rcd,s give earth leakage protection mcb,s give short circuit protection on mcb,s there are 3 different types on new ones say you put a 6 amp one in you need to decide also which type ,b,c,or d normally b for domestic cis for industrial eg motors or d type eg transformers welders ,it is very rare rcd,s have faulty tripping it is normally a fault on circuits which can be tested ,to answer compatability made to iec or bs speck ,as i spoke before if boat builders do some thing it will have a kite mark or similar if you do it it s an insurance get out in my opinion ,if you have a boat safety cert that may be ok but at sea nothing only hope nothing goes wrong ,note this only my opinion .roy

No, wrong, MCB`s give overload protection

 

[Seastoke]

you are right but if the circuit is designed right it should not be over loaded where a short will create an over load ,what we should be trying to help make sure if something goes wrong people are safe and god forbid a fire starts out you are insured remember your boat mite be along side a boat with **** protection

 

[sailorman]

you are right but if the circuit is designed right it should not be over loaded where a short will create an over load ,what we should be trying to help make sure if something goes wrong people are safe and god forbid a fire starts out you are insured remember your boat mite be along side a boat with **** protection

a "short" will trip the RCD
those 15 Amp fuse wires used to blow on overload

 

[Seastoke]

you miss the point an measures the current flow going down the live and back down the neutral this should be as close as poss now if anything above 30 ma is differential it will trip now an mcb is to protect short circuit say you cut the tv cable which is two core cable ie no earth no way will the rcd trip ,no leakage but you are touching live and neutral together ie massive inrush of current so mcb trips ,safe .for me most of us sleep in the bow and best way out is stern i dont want to be on fire .

 

[nigelmercier]

[waffle deleted] .roy

So you do have a full stop on your keyboard after all.

What was your point?

 

[Daydreamer]

What was your point?

It takes a bit of interpretation but what Seastoke is saying seems straightforward and I think, correct. A L-N fault will cause an overcurrent trip in an MCB, a L-E or N-E fault will cause an Earth leakage fault and trip the RCD. In practice these faults can be difficult to diagnose, particularly if the offending cable is under floorboards.

 

[Seastoke]

point is will insurance pay out ...... as electric is connected to your boat every minute you are not there ,lets all pray

 

[sailorman]

Whats all this cr ap about "will the ins pay" that gets trotted out all the time now.
shore power is allowed & is quite normal these daze. it wasnt common 40 yrs ago

 

[Seastoke]

if you have electrical fire anf wiring is not fit for purpose would they pay out ,is there an insurance guy who could pass comment .