Thread: Stupid things you discover

Had a sparking power point in my first house some 35 years ago. Went to replace it and saw bare wires at least 100mm up the wall. Old rubber insulation wiring!!!
On a house we inspected recently the switchboard was dripping with green verdigres. So wiring issues seem to abound.

Originally Posted by austastar

Hi,
They were called Earth Leakage Circuit Breakers

I thought they still were ! What does RCD stand for then?

Hi,
Residual Current Device? (maybe??)

Cheers

Originally Posted by austastar

Residual Current Device...

Correct. They measure the difference between the current in the active and neutral wires, any current above a threshold found when you subtract N from A is the residual current and trips the breaker. An earth connection isn't actually required.

There are new rules concerning RCDs coming in soon.

Now have to be on permanently wired devices such as cooktops,hot water systems and AC units in domestic/residential.

Commercial, on all lighting,and socket outlets up to 32 A,and also fixed wired equipment up to 32Amp circuits.

That should make things a lot safer,but the down side is nuisance tripping,particularly when it comes to important equipment,such as refrigeration.

You say "a lot safer" - but actually, how many fatalities are there from these devices? Certainly safer, but is the improvement significant?

Originally Posted by scarry

.......,but the down side is nuisance tripping,particularly when it comes to important equipment,such as refrigeration.

Hi,
I had the fridge, hot water and a 20A socket in the workshop left off the RCD circuits for that reason.
We do get nuisance tripping with domestic irons in the laundry, some times our portable hot plate will trip the circuit, and a Fowler bottling urn does the same.
I can't fault the wiring with the multimeter, but it sure is a pain sometimes.
Cheers

Originally Posted by austastar

Hi,
I had the fridge, hot water and a 20A socket in the workshop left off the RCD circuits for that reason.
We do get nuisance tripping with domestic irons in the laundry, some times our portable hot plate will trip the circuit, and a Fowler bottling urn does the same.
I can't fault the wiring with the multimeter, but it sure is a pain sometimes.
Cheers

Refrigeration has lots of moisture around and heaters,so nuisance tripping can be an issue.

Freezers particularly have electrical terminals covered in ice and condensation all the time,but pure water does not conduct electricity.Until it gets contaminants in it.

Multimeters often won’t pick up earth leakage faultsyou need a mega.