RCD Keeps tripping on new installation

[ARW]

Bring back Mr Benn and Bagpuss.

[dennis]

You still only have one feed. If not having lighting makes it dangerous you need to do more than fit two RCDs. Maybe a maintained light fitting.

[Owain]

One of my 'jobs' was to sit on the spin dryer to stop it dancing round the kitchen.

Another 'job' was to sit on dad's workbench to stop it dancing round the bedroom whilst sawing.

And Open University on Sunday mornings.

Owain

[tony sayer]

Just for the benefit of the OP as it seems some aren't that clued up on RCD's...

All an RCD is, is a differential detection system.

It monitors the CURRENT flowing into the protected circuits and the CURRENT flowing out.

So what comes IN on the LIVE wire must be the same as what goes OUT on the NEUTRAL.

If there is a bigger difference than the rated tripping current of the RCD or for that matter RCBO then the device will trip.

Normally this is caused by a leakage to Earth somewhere in the protected system. This can be like a cooker element where there is a breakdown of the insulation of the material the element is enclosed in, or say a washing machine where the motor might be rather wet and the currents from the live are "leaking" across to the protective earth or sometimes thru a person who comes into contact with the live conductor.

So as long as what goes in on the Live comes out on the Neutral sometimes referred to as the return, then all will be well unless that current in on the live finds a path to Earth that does NOT go out on the neutral return line.

What can cause some confusion is the Earth - Neutral short.

Now this can exist with the RCD closed and remain so as long as there is NO current flowing in the circuits.

Consider that nothing at all is switched on in the protected system then the LIVE incoming has nowhere to go at all hence nothing is going out on the Neutral return so No difference in flowing currents in the RCD and no resultant tripping.

So you can have a Earth - Neutral short and it can, as long as nothing or almost nothing is switched on, then there will be no trip.

However if now say something is switched on then current will flow in on the Live and it won't all go out on the neutral as there is an earth neutral short so some of it will go out via the Earth path and not all of it will go out thru the RCD hence there is a current unbalance set up and out will go the trip provided that the current differential is greater then the tip's rated current..

If the current drawn by the connected load is very very small then there may not be sufficient differential of the currents thru the RCD and it will stay UN-tripped but as soon as that current rises above the tripping level out will go the trip.

Of course a resistance test/s will or should show up the earth neutral short.

So simply the RCD or RCBO is a Current differential device which means that the current in MUST be the same as the current out if those currents differ by more then the rated tripping current then the trip with do what it does best .. and trip;!...

[tony sayer]

Not always.

Consider a house that might be in multiple occupation or where the battery backup might not be that good or some buggers have "borrowed" the backup batteries or not renewed them.

Isn't it better to have that on a lightning circuit which will be noticed if its Off a lot quicker then the fire detection system as tripped which in a lot of cases won't be noticed all that readily?...

[Peter Parry]

Is that why hundreds more people are injured by falls in the dark than by electrocution every year? It seems risk assessments are something else you don't understand.

means harm by electricity.

Where in the regulation you refer to does it say "electrical hazard"?

[Tim..]

Check the IR of the affected RM. But first, are you sure you have the N's in the right busbar as assuming it will be a split load dual RCD CU ?

[ARW]

And how many of those hundreds fell over because they had a RCD main switch that had tripped?

It cannot be many.

In fact it more people have probably had their lives saved by a RCD main switch than have fallen down the stairs caused by a main RCD switch tripping. Of course the life saving RCD trips are not recorded as they are non events.

[philipuk]

Brilliant trolling here methinks. Got the usual suspects very hot under the collar.

Philip

[Andy Burns]

Nah, it's a banter user, they probably forgot the name of the website they went to in the first place ...

[John Rumm]

>>>>>

That was common on TT systems under the 16th edition. The cable protection requirements make it less workable for new installs.

[Tim Watts]

I still vot etroll, as I did 2 days ago.

If he had any sense, he would have found the IET forums - they have awhole section for professional sparkies.

[Bill]

In message , Tim Watts writes

If he is then he has done very well, 111 replies so far!!

Maybe it is time he owns up one way or the other?

[Doctor Drivel]

It is NOT an electrical hazard.

Where does say anything else?

[Doctor Drivel]

Good point, but the smoke alarms have an indicator light.

[Doctor Drivel]

Good point.

[Peter Parry]

A lot more than are killed by electrocution. A bulb fails, that takes out the RCD and an elderly lady is left in the dark trying to find how to rectify the situation. They find the stairs by falling down them. I'm aware of at least a dozen cases where emergency services responded to calls to fatalities and found lights inoperative on arrival and that is only within one county area.

Actually electrocution is, and has been for quite a long time, a non-event in domestic premises with casualties below 10 per year throughout the UK. On the other hand falls and fires kill thousands each year. Many occur at night and if the house is on fire the last thing you want is for the electrical system to "protect" you by switching everything off.

It is the failure to do joined up risk analysis which led to mistakes like Part P which increased the number of deaths.

[polygonum]

Sounds very plausible. And so the obvious answer is to fit emergency lighting as a priority over worrying about RCDs, etc.

[Bill]

In message , polygonum writes

I have fitted emergency lighting in all the places that I felt necessary, main bedroom, inside windowless bathroom, landing at the top of the stairs and utility room above the fuse box. I have never regretted the expense of this and it has proved useful on a number of occasions over the years.

There again I also fitted a 7.5 KVA generator in the garage, with an emergency light above it too. My wife does mutter that the house is a bit "industrial" but it is also relatively worry free when we have RCD trips and power cuts.

[tony sayer]

In article , Doctor Drivel scribeth thus

Yes, and how many would remember to look at those especially in HMO's?.

Whereas a main lighting failure would be acted on a lot more quickly!..