should this trip an RCD ? L-bulb-E

okden

if i temporarily connect a light bulb between Live and Earth should the RCD trip ?

2011

okden wrote: »

if i temporarily connect a light bulb between Live and Earth should the RCD trip ?

If fed from an RCD, yes.

2011

Just to add, I would not rely 100% on the RCD functioning properly. They have been known to fail and as such should only be used as supplementary protection.

Also it is not a good idea to experiment with mains voltage electricity.

Tuco88

Lol that reminds me of an old electrician I knew years ago.

He used to check the operation of the rcd with 3 bulbs, I think 60/75/100watt bulbs. He had a plugtop with a 3 gang switch rig made himself.

No F1 style stop watch tho ��.

Bruthal

Tuco88 wrote: »

Lol that reminds me of an old electrician I knew years ago.

He used to check the operation of the rcd with 3 bulbs, I think 60/75/100watt bulbs. He had a plugtop with a 3 gang switch rig made himself.

No F1 style stop watch tho ��.

Its a decent way of checking that they at least operate.

I used to do similar with a solenoid test lamps that used to draw just enough to trip them. But at sockets through the installed RCD.

Anything from 6w down L-E shouldnt trip one.

Tuco88

It was probably the 300ma rcd on TT systems he was checking at the time, By those lamp sizes. I definitely remember 60watt being one and working out the mA.

A real tradesman shirt and tie to work and was ahead of his time.

Thomyokk

Tuco88 wrote: »

It was probably the 300ma rcd on TT systems he was checking at the time, By those lamp sizes. I definitely remember 60watt being one and working out the mA.

A real tradesman shirt and tie to work and was ahead of his time.

Would that work though with incandescent due to the inrush current.

Some voltage testers will/won't trip then although I never looked too closely at the input impedance

Bruthal

Thomyokk wrote: »

Would that work though with incandescent due to the inrush current.

Some voltage testers will/won't trip then although I never looked too closely at the input impedance

Interesting question there alright.

60 watt bulb is just below the 300ma RCD.

A 60 watt incandescent one will be momentarily around 600 watts, definitely for long enough to trip if its a 30 ms type 300ma RCD, although the time taken to trip will likely be longer on those ones, and there are are time delay ones to.

Tuco88

Yeah the S type. Id actually like to try it out see the results some day.

okden

thankyou,

the longer story is i have an outside security lamp that needs replacing, it is near the fusebox with a 3 wire (LNE) fused switch spur feed (fusebox-switch-lamp)

but i have a vague memory of an electrician once saying something about one of the outside lights wasnt strictly to code but was ok

i was trying to figure out if the earth was really connected to this outside security lamp and earthing to ground or should i replace it with a 2 wire (LN) double insulated plastic lamp for added safety


before any wiring i turn off all electricity at mains


i tried to test if the earth was really earthing to ground by temporarily connecting a bulb live to earth at the fused switched spur for this lamp (L-bulb-E) and the RCD did NOT trip

if i manually turn off the downstairs light RCD this temporary bulb does go off


the downstairs lights are 2 wire (LN)


so seems to be one RCD with 2 lines out, one for lights downstairs, and one for the outside security lamp, then this outside security lamp feed is also tapped into earth near the fusebox somewhere


the earth seems to be connected to ground ok (bulb lit) but the rcd didnt trip (bad rcd) ?