New Spots Cause Flickering and Fuse Trip

[TheHoggleDog]

Hi,

First post so go easy :/

I've done a fair amount of electrical DIY, confined mainly to changing light fittings, adding a ring main spur in at the most, so fairly simple stuff - nothing that changes circuits on the whole.

But yesterday I added some spot lights into a WC room and now the downstairs lighting circuit keeps tripping once all downstairs lights are on for an amount of time.

Outside of this room I also recently put up a two arm / four spot (35W each) cheapo set of spot lights (Homebase special, you know the sort). When I put this up one of them has always flickered a little when it first goes on, I've been meaning to take it back down and check the wiring but haven't as yet, mainly cause it was such a pain to get up in the first place. This happened before the install of the three new spotlights, although the norm is to see the light flickering then it tends to stop and it's OK after that.

So I put the spots up, I took the supply and switch cable that was originally installed into a ceiling rose through a choc-block and pulled off three 1.5mm2 cables to the three new spots. Each spot is a 50W halogen. The 1.5mm2 is twin+earth but as the units are double insulated I just cut back the bare earth wire inside the insulation.

Now when I have aforementioned cheapo two arm / four spot on AND the new three spots, after about five minutes the circuit trips, this is normally preceded by an amount of flickering from the two arm / four spot light outside the WC and the kitchen lights.

I haven't yet done much fault finding, but I'm initially wondering if anything I've done with putting the new spots up could have overloaded the circuit? I wouldn't have though it would / could. Is wiring the supply and switch cable into the choc-block a bit of a no-no?

Could a dodgy earth be causing the fault (either in the two arm/four spot fitting or the choc-block)? Looking for a little guidance before I start taking everything down and testing. Everything I've done can be easily reversed if needs be.

Thanks

 

[BluSparx]

My advice here would be to get a Qualified electrician to have a look and fault find for you.

There could be a number of issues here which if you do not have suitable fault finding experience/training could make it worse than already is by poking about with different checks.

I'm sure somebody on this forum would be close to you who could come and have a look, failing that definatly ask a qualified electrician to have a look for you.

 

[TheHoggleDog]

There could be a number of issues here which if you do not have suitable fault finding experience/training could make it worse than already is by poking about with different checks

Hi, thanks for your input.

For the moment I haven't done anything other than change light fittings; the house is only 15 years old and all the wiring is in very good condition; there was no tripping before hand so I'm sure it's something with the new fittings. If I can't solve this by simple things like checking the earths are good, etc., then of course I would consult a sparky, goes without saying. I certainly wouldn't think of going any further than some very simple wiring checks; I was mainly wondering whether a dodgy earth connection could 'possibly' cause an issue as described and furthermore whether the choc-block wiring is suitable. For e.g. before paying a call out I would rewire with lighting JB's if wiring could be an issue, I can't imagine that 3 x 50W spots are suddenly maxing the circuit out. Thanks for your advice though, it is appreciated.

 

[ukpablo]

what is it tripping? mcb or rcd?...........i assume its the mcb as it is only happening after a period of time???

I agree with blusparx, u need to perhaps ir test the cct, check polarity of cables etc.........may be poor insulation or a nic in the cable............or overload of cct????........could be a number of things?

 

[Deleted member 9648]

Add up the wattage of all the lights on the circuit,,,(or all the lights likely to be on at the same time)....divide the total wattage by 230v and the result will be the current in amps the circuit draws....if this exceeds the rating of the protective device it is overloaded. Although this method doesnt take into account all the factors involved in working out the effective load on the circuit it is fine for a DIY spot check.
If you establish the circuit is not overloaded a check by a qualified electrician is essential and advisable whatever.The only way to prove the circuit is ok is by proper testing.

 

[Sparky Ninja]

I would check out the loading of the circuit.
Also it may be a good idea to remove the flicking fitting temporarily, and see if the circuit then stays on.

What's your location mate?

Is this your own DIY or handyman kinda domestic work?

 

[ezzzekiel]

yup sounding like overload to me,

test equipment?
partp?
bonding?
rcd?
competant?

 

[TheHoggleDog]

I would check out the loading of the circuit.
Also it may be a good idea to remove the flicking fitting temporarily, and see if the circuit then stays on.

What's your location mate?

Is this your own DIY or handyman kinda domestic work?

Try this again, last reply didn't make it.

It's my own DIY, it's the MCB tripping, not the RCD

Total wattage possible at trip was 521W (~2.2A). Circuit / MCB is rated at 6A (I think, although I haven't looked again)

I've removed the "flickering" unit from the circuit with all other lights on and it hasn't tripped again (20mins+)

Seems to be something in that / to do with that unit rather than the new spots

Luke

 

[Sparky Ninja]

I would suggest keeping that fitting as your prime suspect. Can you inspect it's connections while it's disconnected?
If the rest of the circuit stays on, then change that fitting if you can't repair it.

If the circuit does go off, let us know and we will talk about the spots.

 

[nickblake]

sounds like a wiring error on the fitting crossed wirng ie ins and outs mixed so it goes through the lamp wiring it in series hence the flickering or as has beeen said a faulty fitting

 

[darren balchin]

Hi,

First post so go easy :/

I've done a fair amount of electrical DIY, confined mainly to changing light fittings, adding a ring main spur in at the most, so fairly simple stuff - nothing that changes circuits on the whole.

But yesterday I added some spot lights into a WC room and now the downstairs lighting circuit keeps tripping once all downstairs lights are on for an amount of time.

Outside of this room I also recently put up a two arm / four spot (35W each) cheapo set of spot lights (Homebase special, you know the sort). When I put this up one of them has always flickered a little when it first goes on, I've been meaning to take it back down and check the wiring but haven't as yet, mainly cause it was such a pain to get up in the first place. This happened before the install of the three new spotlights, although the norm is to see the light flickering then it tends to stop and it's OK after that.

So I put the spots up, I took the supply and switch cable that was originally installed into a ceiling rose through a choc-block and pulled off three 1.5mm2 cables to the three new spots. Each spot is a 50W halogen. The 1.5mm2 is twin+earth but as the units are double insulated I just cut back the bare earth wire inside the insulation.

Now when I have aforementioned cheapo two arm / four spot on AND the new three spots, after about five minutes the circuit trips, this is normally preceded by an amount of flickering from the two arm / four spot light outside the WC and the kitchen lights.

I haven't yet done much fault finding, but I'm initially wondering if anything I've done with putting the new spots up could have overloaded the circuit? I wouldn't have though it would / could. Is wiring the supply and switch cable into the choc-block a bit of a no-no?

Could a dodgy earth be causing the fault (either in the two arm/four spot fitting or the choc-block)? Looking for a little guidance before I start taking everything down and testing. Everything I've done can be easily reversed if needs be.

Thanks

hi never cut the earths of, just sleave them up as further light fittings may need a earth connection,check all the connections are tight and you havent screwed down onto the insulation,it does sound like the circuit is marginally overloaded as circuit breakers will run above thier rated current for a time a usual indercation is that the breaker is hotter to touch in comparison to the other circuit breaker's,but i do agree that it is better to have it checked by a competent sparks because thier may be other problems which could be dangerous.

 

[TheHoggleDog]

Just to update ... Yesterday I took the offending unit down and powered the circuit with all the lights on minus the flickering two arm / four spot fitting. That proved to be the suspect fault in the circuit. It's a mainly prewired fitting so I attempted to reinstall it with the terminals rewired but it tripped again. When I took it down one of the neutrals had popped out and caused a big short circuit and completely blown the MCB at the CU! D'oh! Cue the qualified spark!! He replaced the MCB for me today and OK'd the circuit. For the moment I've reinstalled just a bulk standard ceiling rose pendant and the circuit is operating fine. The two arm / four spot fitting is heading for the tip. Thanks to everyone who offered advice, very much appreciated!

Luke