Junction box intermittently shorting (possibly)

[topman870]

I've currently got a 10way honeywell... its being shorted somewhere (I think) but strangely it's not consistently and struggling to find out what's causing it... everything connected to the junction box would die..the CU is RCD protected but doesn't trip.. switching off the fuse spur on/of makes no difference but as soon as I rock it on/off from the MCB everything powers back on.

The junction box is a joke as I've got 4MVs and it's all wired into a 10way! It's been working perfectly fine for the past 3 years....

It happens randomly and yesterday I noticed all my neo stats went off at 5.40am but came back on straight after... Today I heard some static noise from the neo stat in my bedroom and everything went off around 5am... Hot water is calling for heat between 4:30-5:30am...and downstairs heating is calling between 5-6:30am

Power for the fuse spur is taken from a utility ring which only has 2 sockets for a spare fridge n washing machine. I didn't pay attention if the fridge was still powered at the time... Will need to check the next time it happens.

Im thinking of sorting out the junction box as it's a total mess and issue may we'll be in there... Any recommendations on which junction box I should opt for a cleaner install?

Thanks!

 

[topman870]

Hey guys,

Today everything just cut off and I'm not getting any power to the boiler heatmiser UH8 or any of the neo stats...I've tested that I've got live coming into the junction box... can't seem to get it going anymore... Any suggestions on what I can test...

 

[CBW]

What have you tested between for voltage? Sounds like a possible loose connection.

 

[topman870]

Just tested live to the junction box n boiler using a tester screwdriver which was live...

Strange that it happens in the mornings... If the over heat stat in a unvented was to kick in would it trip out everything? Shouldn't do unless it's wired incorrectly?

Thanks

 

[conny]

You need to use a meter to test properly. A neon will show if there is a live but you need to see if there is a continuous circuit.
Have you got a 2 lead multi-meter? With the power off you can set it to Ω and check for continuity then set it to V once the power is back on and check you are getting a voltage through each circuit. If you have a loose connection, it will not show with the neon. The above tests may show there is a fault on the neutral side, (where the neon won't show).

 

[topman870]

Yep i've got one.. only ever used it for basic continuity. you could be correct about the neutral.. after several on/off its back...

Sorry what you you mean about the neon bit?

maybe when its drawing current something is going on...

 

[conny]

If you touch a 'Live' supply cable with a neao, it will glow. If you touch a 'Neutral' with a neon, even if there is power flowing in it, it will not glow so you may think it is dead. One of the reasons I don't like neons.

 

[CBW]

Just tested live to the junction box n boiler using a tester screwdriver which was live...

Strange that it happens in the mornings... If the over heat stat in a unvented was to kick in would it trip out everything? Shouldn't do unless it's wired incorrectly?

Thanks

Afaik - if an overheat trip were to activate, it would only cutout the appliance, not kill the electrics. One thing that could be wired up to it is a condensate pump, which can be wired to knock power off, but that’s usually a boiler.

As per @conny - you need proper test equipment, not a neon screwdriver.

 

[old duffer]

Using simple logic it would suggest that if it's worked fine then why suspect the wiring to be at fault?
You mentioned a thermostat...which operate on very low resistance and will eventually fail.
Its not the wiring, its a component issue

 

[topman870]

If its a component issues can it be intermittent? also would it take out all controls... the only 2 things I have going on/off is hot water and heating... in the morning there is an overlap between the two.