scenaro

[domestic spark]

Type B 60898 hager MCB 32A. MCB for Kitchen ring, trips when a few appliances are drawing load. ie, washing machine is running a cycle, kettle gets put on, and maybe toaster.

trip. (MCB only)

looked at this side of the kitchen. only one 2.5mm t&e comming from ceiling (must be jb unaccessable somewhere) to double socket above worktop. from this spur off to under counter lights. then spur to 3 single sockets under counter for various appliances then finally a double socket further over the counter.

all tests at fuse board fine insulation resistance, acceptable zs values, continuity of ring condictors etc.

now, r1+r2 readings 0.24, 0.28, 0.32, 0.44 at last point (double socket) confirms its a radial (spur off spur off spur)

over other side of kitchen readings of 0.05, 0.06 0.06/7.

as this 2.5mm cable has been spurred off 5 times would this be why its tripping MCB as cable is OVERLOADED?

i dont want to rewire whole ring final, for the same problem to occur. obviously!


am i on the right track here guys cheers!

 

[bugsy]

When you say a few appliances are these allat once , W/M heater 3kw , kettle 3kw 25a , toaster 2.3kw 9.98a total 34a does this circuit supply anything else? you say theres a JB in the ceiling have you checked to make sure it dosent feed the water heater or something stupid?

 

[domestic spark]

it happens when washing machine is on a cycle and kettle is put on or both kettle and toaster. for some reason half the kitchens been spurred.

KITCHEN RING on its own dedicated circuit.

im presuming JB hidden above ceiling as only one 2.5mm t&e drops down to double socket above worktop. from this spur off to under counter lights. then spur to 3 single sockets under counter for various appliances then finally a double socket further over the counter.

and radial confirmed by rising r1+r2 readings.

done a full test on circuit and all readings were ok.

 

[domestic spark]

i just want to be sure the cause of the problem, dont want to rewire and MCB trips!

 

[domestic spark]

one thing i will do though once there again before i start work is to check that immersion is on its own circuit and not off of kitchen ring.

 

[bugsy]

Well if that lot's on one spur then rewire it it exceeds CCC of cable anyway

 

[domestic spark]

would this cause a 32a breaker to trip though? by that i mean the only wrong thats happening here is, your overloading one 2.5 mm cable as your pulling way more than 27a through it, at best

 

[bugsy]

check to see if some silly badger bodgit has fed another load of it , sod's law say's they have

 

[Jurasic Spark]

i just want to be sure the cause of the problem, dont want to rewire and MCB trips!

The c/b doesn't care whether its supplying a RFC or a Radial, it is tripping due to overcurrent which means your radial 2.5 is exceeding its CCC.

 

[domestic spark]

The c/b doesn't care whether its supplying a RFC or a Radial, it is tripping due to overcurrent which means your radial 2.5 is exceeding its CCC.

so jurasic spark, if a 2.5mm spureded cable IS overloaded, MCB will trip? even though its a 32A breaker.

 

[domestic spark]

*spurred

 

[bugsy]

I think your missing the point

 

[domestic spark]

someone please clear this up

 

[telectrix]

needs further investigation. unplug all appliances in kitchen. clamp meter 1 leg of ring in CU. see if any current flow. clamp meter other leg . ditto. plug in one appliance at a time . meter both legs ( one then the other, not together. ). looks like a fair bit of rewiring needed. get rid of spurs. maybe the MCB has gone a bit tired after being heavily loaded for so long.

 

[domestic spark]

my logic was as ring has been spured 5x this is causing MCB to trip. my solution was to rewire to a proper ring, no spurs in 2.5 t&e and this would sort MCB tripping issue AM I WRONG?