Electrical gremlins in the house - Sparky advice appreciated.

[Nomad]

Todays brain teaser
I'm staying at a relatives house for a few weeks and house sitting while they're away.
The family have lived here for years and I often stay over for a few days when I'm visiting them.
This time I've noticed a couple of things that are not right, I'll fix them if I can but I need to know what's causing the problem first

The lounge light won't turn off.
It has a single simple on/off switch
The light is either *On (as expected) or *Dim (when it should be 100% *Off )
Bulbs are 3 off G9 LED's
Any suggestions?

Question: If the on/off switch is in the neutral line rather than the live feed, would the "constant live feed" be enough to make the LEDs glow - even without a neutral return line?


The shower keeps tripping the fuse.
Fusebox is a metal clad split-load unit and looks quite recent.
The Bathroom had a total refit and new shower fitted about 5 years ago, I think the problem has been here since then but it's getting a lot more frequent ( 3 times in 1 morning last week !)

Background:
There's a bathroom fan on it's own switch. Bathroom light must be on to turn fan on, fan stays on until fan is switched off - even if the light is turned off first. Some kind of latching system - I think this runs from the lighting circuit only - but I'm wondering if it's hooked into the shower circuit somehow and causing the tripping?
Shower has a "Low pressure" window, normally this shows white (good), yesterday it showed 50% white / 50% red - so lower than normal but it didn't cut out.
I've not paid attention to the low pressure flag when the shower has tripped but I'll check next time.

Question : would low pressure cause the fuse to trip, if not - what would?
I'm close to getting the trip switch in the fusebox replaced but would like suggestions before I do anything.


Help

 

[brightspark]

that shower mcb has tripped what size shower and what size mcb.if its 8 kw or over it wants to be a b 40 amp

 

[GRW]

1. I'd check/replace the light switch. It seems most likely (& easiest to try) that the switch isn't breaking the supply to the lamp properly/completely.

2. What rating in Amps is the Breaker fir the Shower? It might be too small. Older Shower was quite likely 6, 7 kW, where the new one is probably 10kW.... so the old one would be OK on maybe a 32A breaker, but the new one would need a 50A

 

[bump]

Possibly induced current in the lighting wiring causing the glow.

Tips to Stop LED Lights From Glowing When Off | LEDwatcher

#post_excerptIf you’re wondering how to stop LED lights glowing when off, here’s our quick guide.

www.ledwatcher.com

 

[Nomad]

Thanks everyone - @brightspark I was hoping you would notice the thread

Shower is Triton model T80, 10.8Kw
MCB is 40A
Distance between fusebox & shower is about 4 meters ( fusebox is on ground floor, shower directly above it on the first floor, shower isolator switch about 1 meter horizontal from the shower - on the other side of the wall not inside the bathroom )

 

[brightspark]

if theres a slight shin

Possibly induced current in the lighting wiring causing the glow.

Tips to Stop LED Lights From Glowing When Off | LEDwatcher

#post_excerptIf you’re wondering how to stop LED lights glowing when off, here’s our quick guide.

www.ledwatcher.com

possibly it mainly happens on a 2 way circuit a bit of residual current hanging around

 

[brightspark]

Thanks, I was hoping you would notice the thread

Shower is Triton model T80, 10.8Kw
MCB is 40A
Distance between fusebox & shower is about 4 meters ( fusebox is on ground floor, shower directly above it on the first floor, shower isolator switch about 1 meter horizontal from the shower - on the other side of the wall not inside the bathroom )

change the breaker to a 50 amp if its tripping after a minute or so

 

[Nomad]

Quick answers and simple solutions - it's much appreciated !

Lights are aren't a 2-way system, only 1 switch, looks like better quality bulbs will be the quickest thing to try. I suspect the ones in there now are from the pound shop.

Shower is odd, some days it's fine, other days it cuts out several times. I'll try swapping the breaker and see what happens.

 

[brightspark]

the fan probably runs of the bathroom light and has a fan isolator switch fitted .when the lights on the fan comes on when the lights turned off it has an overun timer that can be set to 25 minutes after light is turned off. the fan isolator will kill it instantly if turned off and the lights still on

 

[MetalMonkey]

1) Common issue with LED bulbs due to Capacitive coupling/Induced voltage. Some bulbs will incorporate a snubber circuit to deal with this, or you could add one if you have the space.
In the unlikely event you have two plate (neutral in the switch) then you could fit a double pole switch which should cure it.

2) As brightspark says, fan probably has the permanent and switched lives taken from the light and a separate isolator in the switched line. It won't be connected to the shower in any way. At least. I would really hope not!

One thing I would add is check the cable size and consider how it is installed (is it in trunking, clipped or buried in the wall, running through insulation etc) before upping the MCB, 40A might already be the maximum.

 

[gaz1]

if on old wiring you can have issues with leds

depends on how someones wired the house up

for me it was bright light turn them off and they flickered with low light on them

https://www.mig-welding.co.uk/forum/threads/workshop-build.83872/page-6

 

[Matrixx]

For the light i would check the neutral, could be back feeding through something. ideally you would check the voltage at the light socket on/ off.

If the RCD is not tripping then it's just current related, but you can get duff MCB's, maybe swap with another one? I would stick a clamp meter on with a peak current hold function to verify what the actual loads are.

 

[Martin-Sy]

10.8kW on 230V mains is 47A
Even if your on 240V it's still 45A.
I too would be concerned about the cable size if the shower unit was changed but the wiring left as was.

Dim light: Yes, capacitive coupling between the live and the switched live when the switch is off.
We had a hall light that used to flash every few seconds when off.

 

[ajlelectronics]

"https://www.ledwatcher.com/stop-led-lights-glowing-when-off/...

• There is a neutral wire within the electric circuit that isn’t bonded with the earth."

 

[dobbslc]

Question: If the on/off switch is in the neutral line rather than the live feed, would the "constant live feed" be enough to make the LEDs glow - even without a neutral return line?

Yes I had it on a led floodlight, where the neutral was switched.

"https://www.ledwatcher.com/stop-led-lights-glowing-when-off/...

• There is a neutral wire within the electric circuit that isn’t bonded with the earth."

@Nomad Is it a TT earthing system? ie on an earth rod.

Probably just crap lamps but worth checking the switch.

The shower would be worth checking the cable size before changing the MCB. Would a low water flow cause the shower to overheat and raise the current draw just enough to overload it if it is already on its limit after being upgraded to a 10kw job?

 

[MoreWellie]

My parents old house was originally on a DC main and the board didn't change the feed cable when they were changed over to AC. The board earth just connected to a local ground spike

Depending on how damp the weather was you could measure up to about 60 to 80 volts between neutral and ground. With the original fusebox (rewirable) fitted you could turn off the mains (live only isolator) and still get bangs and sparks when working on the house wiring

 

[Nomad]

The shower is happier now I’ve fitted a new breaker. Same 40A spec as the old one, difference is this one doesn’t trip and the shower water runs a lot hotter. Nice !
I’m guessing some poor internal contact on the original trip switch but it’s on it’s way to the bin so not important.


Shower is the breaker on the right.
Do the wires on top of the next trip look ok? Insulation looks blistered but not cooked. Odd.

 

[brightspark]

The shower is happier now I’ve fitted a new breaker. Same 40A spec as the old one, difference is this one doesn’t trip and the shower water runs a lot hotter. Nice !
I’m guessing some poor internal contact on the original trip switch but it’s on it’s way to the bin so not important.
View attachment 383126

Shower is the breaker on the right.
Do the wires on top of the next trip look ok? Insulation looks blistered but not cooked. Odd.

that looks like the ringmain. there could be a cable break on the live wire and half the ring may be taking all the load instead of sharing it. turn the breaker off take a socket off that is on the ringmain part the cables and test each leg with a voltage meter live and neutral should be about 240v on each leg if there isnt and only on one theres a break in the line. a ring will still work with a broken cable

 

[dobbslc]

Also worth checking that blistered cable is actually tight in the terminal, often one gets clamped but the other is just floating.

 

[brightspark]

Also worth checking that blistered cable is actually tight in the terminal, often one gets clamped but the other is just floating.

yes if there is a break it oveloads and burns out at the weakest joint