- Thread starter Seano
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wheresmejumper
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an rcd detects earth leakage,e.g. an earth fault
an mcb detects overcurrent
an rcbo does both
an mcb detects overcurrent
an rcbo does both
Seano
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So therefore it makes sense to fit the latter..... didnt realise how expensive enclosed standalone RCD's were
, if thats that correct term.
wheresmejumper
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it depends really whats on the circuit,what it would cost,and overall size needed/available on the consumer unit
it might be cheaper to buy 1 rcd and 10 mcb's,than 10 rcbo's
it might make sense just to add a single mcb to already rcd protected group
other cases,where a risk of electric shock might be higher,like where water heating is involved,an rcbo would provide better protection.might be marginal,but youd sleep easier anyway
older,but still commonly available,rcbo's take up 2 units each on the CU.
newer ones take up a single space
it might be cheaper to buy 1 rcd and 10 mcb's,than 10 rcbo's
it might make sense just to add a single mcb to already rcd protected group
other cases,where a risk of electric shock might be higher,like where water heating is involved,an rcbo would provide better protection.might be marginal,but youd sleep easier anyway
older,but still commonly available,rcbo's take up 2 units each on the CU.
newer ones take up a single space
Seano
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Am thinking more along the lines of fitting them inline above my welder plugs, 32a and 16a, just as an added precaution, my cu is fitted with 32a and 16a mcbs.
wheresmejumper
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have you a seperate cu in the garage?
if you have,its fairly unnecessary to fit more protection,id only do it to save running back to the house cu to reset a trip.
if you have,its fairly unnecessary to fit more protection,id only do it to save running back to the house cu to reset a trip.
Seano
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Think maybe we are talking at x purposes, ok picture this, cu is at the back of the garage, it has had a 16 & 32 amp mcb fitted, the feeds are then taken from there to the respective 16 & 32 amp commando plugs fitted on the wall, the idea is to introduce two standalone rcd's or the new rcbo's into the supply to each socket as an added safety.
AndyStobbs
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Sounds like overkill.
This CU in the garage, is fed from a CU in your house?
What protection is fitted in the house CU to cover the garage?
This CU in the garage, is fed from a CU in your house?
What protection is fitted in the house CU to cover the garage?
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Is the garage feed protected by an RCD?
Seano
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Yes, the cu is in tha back of the garage which has been partitioned off as a garden shed, with part height block wall and a door leading into the garage, the cu is fed direct from the incoming live main with an RCD on that end, then a a row of various mcb's with another RCD fitted at the other end, if what I am asking about is overkill then fine, just that the sparks who wired it all up for me mentioned it might not be a bad idea for the future.
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You already have enough protection, adding more RCD's will just cost money and may cause "nuisance tripping" where the closest RCD doesn't trip, but one further upstream does.
Seano
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normspanners
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I am not a sparky, but should you not, have the cable supplying the garage protected, not particularly by an rcd but by a double pole mcb unless your cable is 25mm. because it is coming off (by your explanation) the direct incoming main (hopefully not!) but the meter tails to your CU , so therefore does not have overcurrent protection.
I am in the process of doing this and was going to Current protect my SWA Garage supply with a DP 80A MCB then a 100ma inline rcd then a metal clad split load CU in the garage with 30ma rcds so that I dont have to walk back to the house if I trip the leccy
I am in the process of doing this and was going to Current protect my SWA Garage supply with a DP 80A MCB then a 100ma inline rcd then a metal clad split load CU in the garage with 30ma rcds so that I dont have to walk back to the house if I trip the leccy
AndyStobbs
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A few people in this thread have cited avoiding long walks to the house to reset tripped devices. Surely if your protection devices are tripping with any regularity, then either your equipment is faulty or your protection devices are wrong for the application.
wheresmejumper
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a lot of bigger transformer welders can randomly trip with an inrush current,but happily weld away at any amps thereafter.you could upgrade wiring and fusing to cope,but the cost might be greater than the hassle of resetting a trip.
thats one common reason anyway,probably more
thats one common reason anyway,probably more
normspanners
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Correct! But it is the weather that is faulty, trouble is for me a lot of my work is outside and if it suddenly rains and you dont know it has pi**ed on ya chips and extensions etc I would have to walk back in the pitch black whereas if the house was still on I would have light from the pir floods.
brightspark
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im not going in to detail as theres a lot of variables there isnt an 80amp double pole mcb . theres a double pole 80 amp switch disconector which will carry the 80 amp current but wont break at 80 amps. what is needed is an 80 amp switch fuse to protect the outgoing cable to the garrage consumer unit. if the board doesnt supply the earth u would need rcd protection at source and an earth rod fitted best trip would be an 80 amp double pole rcd with a 100ma time delayed trip then fit the 30ma rcd in the garrage or rcbo s then theres no problem of tripping back at source
normspanners
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http://www.ebay.co.uk/itm/400233285...Name=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649I was going to get one of these c rated tripping curve
