is it safe for fridgefreezer to be on rcd circuit

[andemz]

is it safe for fridgefreezer to be on rcd circuit.

If not why not. i read another post when i pumped it intop google and it stated that the fridges are made now a days so that they can be put on rcd circuit.

What are your thoughts

 

[ban-all-sheds]

Safe? 100%

Necessary? 0%

Advisable? You won't think so if you should lose the contents due to a nuisance trip....

 

[brown-nought]

Necessary? 0%

Unless of course you have a TT supply.

 

[andemz]

And if you have a TT supply then what you are saying is that it is necessary....

Why?

 

[brown-nought]

TT supplies don't come with a earth. You provide your own earth with a rod stuck in the ground. Now where as a typical PME/TN-S supply has a low resistance to earth causing large currents to flow to earth during a fault, a TT supply doesn't.

The larger the current flow the faster an MCB/Fuse disconnects the circuit. Earth rod currents may be so low that they never cause a fuse to blow. An RCD detects the imbalance between the current flowing in the Live and neutral wires. Any difference between them is assumed to be "leaking" to earth. If the difference exceeds a low threshold value normally 30ma or 100ma it rapidly disconnects the circuit.

Using an RCD in a TT supply therefore allows the circuit to be interrupted when a earth fault occurs even though the fault current may be to small to blow a fuse.

For the same reason you need to have an RCD when you are supplying tools outside. If you are up a ladder trimming a hedge and clip the live cable the shock current would flow through you, down the ladder to earth. It would be too small to trip the plug fuse etc but large enough to kill you. The RCD would be the only device to save you.

 

[pipme]

Has anyone reading, inadvertantly cut the cable under RCD protection, Was it a shock ?
If electric mower, or hedge clipper has just two core cable in it's own short cord, is there any benefit in using 3 core (L.N.E) extension lead ... with of course, RCD, at least at the socket supplying the extension ?
I bought an extension lead reel, in 3 core seems more versatile to me.
Surely the two core type could be used on the wrong appliance ? i.e. One requiring an earth ? Especially if someone changed the 'adapter or socket end'.
P

 

[andemz]

Yes i had an RCD extension cable pluged into a non recd double socket. I got my nephew to cut the edges for me. We didn't notice that the cable to the hedge trimmer had been previously cut. He acidently touched it with his hand and he got a shock. He described it as a little tingle. It was 2 core wire brown and Blue.

The RCD didn't trip at all.

 

[brown-nought]

If you get a L-N short then the fuse/MCB will blow. The RCD will only trip when its earth leak threshold is exceeded.

Your nephew probably got a painful shock below the earth leak threshold of the RCD. His resistance to earth was high enough to prevent a sufficiently large current flowing. 30ma is believed to provide non lethal shock protection ...but ... it is possible to fit a 10ma RCD to minimise the shock risk further.

Of course your RCD could be knackered … did you test it before he used it?

 

[andemz]

YEAH tested it still is working fine. I've chucked the hedge clippers though. The fuse didn't blow at all.

 

[brown-nought]

Can I ask an unrelated question? What edges did you trim? I’ve an image of you nephew massacring the edge of your lawn … you know the left handed screwdriver gag works better

 

[pipme]

........If you get a L-N short then the fuse/MCB will blow. The RCD will only trip when its earth leak threshold is exceeded.
........

Having rcd plus 3 core extension must help here surely ? I mean if you cut the cable, contacting the live conductor .. isn't there a good chance that you will have cut and cotacted the earth conductor as well ? Thus removing some if not all danger of current through the person ?
P

 

[ban-all-sheds]

Has anyone reading, inadvertantly cut the cable under RCD protection, Was it a shock ?

Plugtop fuse went. The cable action all took place under the mower, so I never saw or heard any fizzpopbang. No RCD trip as there was never an earth fault (2 core cable)

If electric mower, or hedge clipper has just two core cable in it's own short cord, is there any benefit in using 3 core (L.N.E) extension lead ... with of course, RCD, at least at the socket supplying the extension ?

Indeed, as that's the one you're likely to cut through - the integral flex is always too short. AFAIK those rubber 2-pin plugs that you get will go into a 3-pin socket, but I might be wrong.

I bought an extension lead reel, in 3 core seems more versatile to me.
Surely the two core type could be used on the wrong appliance ? i.e. One requiring an earth ? Especially if someone changed the 'adapter or socket end'.

That's the only way it could happen - the only way you could plug an earthed appliance into a cable with one of those rubber connectors would be if someone had replaced the 2-pin with a 3-pin. Ore vice-versa on the appliance.

 

[plugwash]

a line has to be drawn somewhere

it is generally accepted by safety specifications that once someone starts using tools on electrical equipment nothing can really be done to protect them from thier own stupidity

 

[kai]

Going back to original posting - run a 2.5.sq.mm radial off a B16 MCB way, and feed it via a stand alone 13amp PASSIVE switching 30MA RCD protected spur box unit, down to a single 13amp unswitched socket for the freezer.

Passive, means the RCD will not trip on power loss, so your freezer will restart again ASAP when power is back, and you are out or asleep.