Omega Owners Forum
Chat Area => General Discussion Area => Topic started by: pscocoa on 24 August 2010, 19:54:24
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The mcb in the consumer unit covering upstairs lights tripped out at my daughters house. There was no apparent load at the time so suspect it is the mcb itself. Is it possible to test an mcb and how difficult is it to change one of these?
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very easy to change just trip the rcd and that cuts power to the mcb,remove cover and if you have the new one in your hand you will see what holds it on as to how to remove the old one with a blade driver,i changed an rcd today in 5 mins start to finish :y
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The normal issue is that a bulb has blown and taken the MCB out. I would reset it and see if it trips again.
I assume it's not an RCD or RCBO? In that case, you could have an earth leakage fault that has caused it to trip.
Kevin
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The normal issue is that a bulb has blown and taken the MCB out. I would reset it and see if it trips again.
I assume it's not an RCD or RCBO? In that case, you could have an earth leakage fault that has caused it to trip.
Kevin
We have that problem, every time a bulb blows.. ::) ::)
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They also tire with age. Our landlord conducted an extensive wiring test a few weeks ago (took 6 hours) and replaced all the RCDs.
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Thanks - will get onto this now. Even with no load on circuit it still trips out so change of MCB is favourite.
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The normal issue is that a bulb has blown and taken the MCB out. I would reset it and see if it trips again.
I assume it's not an RCD or RCBO? In that case, you could have an earth leakage fault that has caused it to trip.
Kevin
We have that problem, every time a bulb blows.. ::) ::)
halogen bulb ?.
They tend to fail by the element breaking off and falling across the terminals, a shorter bit of element, so tries to draw a lot more current and causing an overload. This used to take out normal bulb dimmers quite quickly, as they can't cope with the momentary surge.
Ken
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...
halogen bulb ?. .....
In our house, 'normal' tungsten bulbs/lamps will pop the RCD when they fail :y.
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Thanks - will get onto this now. Even with no load on circuit it still trips out so change of MCB is favourite.
That doesn't mean there isn't a fault on the circuit. I would disconnect it at the consumer unit and make some measurements before fitting a new MCB.
Does the MCB stay on with the circuit live disconnected from it?
Kevin
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very easy to change just trip the rcd and that cuts power to the mcb,remove cover and if you have the new one in your hand you will see what holds it on as to how to remove the old one with a blade driver,i changed an rcd today in 5 mins start to finish :y
an rcd shouldnt be controlling lighting circuits,at least not over here
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an rcd shouldnt be controlling lighting circuits,at least not over here
17th edition made it a requirement here for
"wiring concealed in walls or partitions at a depth of less than 50mm"
and
"where cables are concealed in walls constructed with metal stud partitions, irrespective of the depth from the surface, unless provided with protection in the form of earthed metallic covering, trunking, conduit or other mechanical protection so as to avoid damage to the cable during installation or construction of the wall."
So, if it's a new install, pretty much everything needs RCD protection. ;)
Of course, it may not be, in this case.
Kevin
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House was rewired in 2005. Box is a Wylex NHRS4504 - I can get the mcbs fom Screwfix in Farnborough whch is very local. Cannot get to it today though.
It may well not be the mcb of course but will start with that.
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House was rewired in 2005. Box is a Wylex NHRS4504 - I can get the mcbs fom Screwfix in Farnborough whch is very local. Cannot get to it today though.
It may well not be the mcb of course but will start with that.
Will the MCB hold in with the mains turned off at the main switch? If so, then there is a load on it which is causing it to trip. It might still be a small load and a faulty MCB,of course, but worth a check before you replace it.
Kevin
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If you turn main switch of CU to off and reset MCB it will hold until you switch on at main switch again.
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Sounds like the breaker is tripping out due to a fault on the circuit to me.
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Sounds like the breaker is tripping out due to a fault on the circuit to me.
Yes, me too.
Kevin
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Replace breaker with M6 bolt, switch on and wait for smoke to issue from the installation. Fault found. Seemples. ;D ;D
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Replace breaker with M6 bolt, switch on and wait for smoke to issue from the installation. Fault found. Seemples. ;D ;D
.. then realise the main switch has welded itself closed and start running around in a panic. ;D
Kevin
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Replace breaker with M6 bolt, switch on and wait for smoke to issue from the installation. Fault found. Seemples. ;D ;D
.. then realise the main switch has welded itself closed and start running around in a panic. ;D
Kevin
Insulated wire cutters through the tails then a plastic bucket to catch the electric that runs out always sorts that.
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Replace breaker with M6 bolt, switch on and wait for smoke to issue from the installation. Fault found. Seemples. ;D ;D
.. then realise the main switch has welded itself closed and start running around in a panic. ;D
Kevin
Insulated wire cutters through the tails then a plastic bucket to catch the electric that runs out always sorts that.
You don't need a bucket with leccy. Must be Gas you're thinking about. :y
Kevin
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there are quite a few recessed ceiling lights and transformers up there to check
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Replace breaker with M6 bolt, switch on and wait for smoke to issue from the installation. Fault found. Seemples. ;D ;D
.. then realise the main switch has welded itself closed and start running around in a panic. ;D
Kevin
Insulated wire cutters through the tails then a plastic bucket to catch the electric that runs out always sorts that.
You don't need a bucket with leccy. Must be Gas you're thinking about. :y
Kevin
Nah Kev, gas you collect with a bin bag and elastic band everyone knows that.
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House was rewired in 2005. Box is a Wylex NHRS4504 - I can get the mcbs fom Screwfix in Farnborough whch is very local. Cannot get to it today though.
It may well not be the mcb of course but will start with that.
Wylex are a good make, we use them throughout all out installs, rewire in 2005 will be to 16th edition, eletricians now works to 17th edition.
There has been a product recall on faulty MCB's by MCB manufacturer Electrium, so if the MCB is an electrium one, you may need to check with the original installers the product codes to see if it is in the batch that are subject to the product recall :y
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Thanks Mike - the CU is indeed Electrium so will give them a call. Thanks for your input.
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The only recall is on units fitted between 1st April 2009 and end of Feb 2010. The Wylex MCB in our unti is NSB06 which is referred to in the recall notice but of course ours was a 2005 installation.
Thanks for the idea on this
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A mate of mine did a re-wire earlier in the year and when he powered it up one of the RCBOs went up in smoke. Would have caused a fire if he'd not been standing there watching it, he reckons. :o Trying to recall what make it was. Could well have been Electrium. I recall that he couldn't get MK ones in the timescale required so went for something less reputable.
Kevin
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The only recall is on units fitted between 1st April 2009 and end of Feb 2010. The Wylex MCB in our unti is NSB06 which is referred to in the recall notice but of course ours was a 2005 installation.
Thanks for the idea on this
Interesting as electrium MCB's fitted in an 06/07 project are subject to inspectiomn by the installer, being paid by electrium , I have access to the codes if you need them let me know. :y
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The normal issue is that a bulb has blown and taken the MCB out. I would reset it and see if it trips again.
I assume it's not an RCD or RCBO? In that case, you could have an earth leakage fault that has caused it to trip.
Kevin
We have that problem, every time a bulb blows.. ::) ::)
halogen bulb ?.
They tend to fail by the element breaking off and falling across the terminals, a shorter bit of element, so tries to draw a lot more current and causing an overload. This used to take out normal bulb dimmers quite quickly, as they can't cope with the momentary surge.
Ken
Some of the 'quality' incandescent lamps have a fusible link in the wire between the base and the filament to prevent a failing lamp taking out the circuit.
You can be certain that the cheap or supermarket ones don't. :(
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as said i would first check the mcb remove the live and try resetting the mcb if it does reset mcb should be ok.
you could then take the live out of the downstairs mcb and put the upstairs on that one and switch back on if it then trips the problem if deffo something on the upstairs wireing.
I would them go in loft see if the roof has sprung a leak if not that have a look round for signs of rodent droppings if not that then its time to start splitting the circuit up
if you need advice on doing this drop me a pm
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problem fixed but took ages and a lesson for all i suspect. After a mate checking MCD and eliminating, then checked all switches, ceiling roses, transformers etc etc. Then to loft everything underfloor boards and eliminated the obvious. Then took view as to which ceiling rose was first feed in from consumer unit, disconnected loop, disconnected switch - MCB immediately held, confirmed feed in with meter. Connected loop and it still held. Connected light switch and MCB popped again.
Fitted light switch in another room and it worked. Fitted temporary switch on short wire to ceiling rose and that worked.
Floorboards then up in loft removed wire and drew through new wire and job finished.
Cannot believe that the wire has just shorted for no reason. It was in trunking, had not been disturbed since installation over 5 years ago, no signs of damage. Anyway job done - thanks to all for contributions