What is a 30mA RCD?

[MWEST85]

 

[pc1966]

RCD stands for "residual current device" and it can be one of several styles, but basically it looks at the current going out on the line/live wire, and the current returning on the neutral wire. Those should match, and any difference means something is going astray.

Worst case it is somebody getting an electric shock by touching live while they are in contact with earth (either metalwork in the house, or really the ground outside) and that is the stray path for the current.

The 30mA = 0.030A is the maximum trip value of stray current which, while painful, is unlikely to be fatal.

These days supply to any out building, garage, etc, should be on a RCD protected circuit, but older installations (or those done badly by "dodgy Dave" from the pub) might not have it.

Can you post a photograph of your consumer unit (CU = fuse box) and anything similar in your shed? Folks on here might be able to tell by looking at what is fitted, etc.

tldr' a safety device against electric shocks

 

[MWEST85]

RCD stands for "residual current device" and it can be one of several styles, but basically it looks at the current going out on the line/live wire, and the current returning on the neutral wire. Those should match, and any difference means something is going astray.

Worst case it is somebody getting an electric shock by touching live while they are in contact with earth (either metalwork in the house, or really the ground outside) and that is the stray path for the current.

The 30mA is the maximum trip value and is 0.03A which, while painful, it unlikely to be fatal.

These days supply to any out building, garage, etc, should be on a RCD protected circuit, but older installations (or those done badly by "dodgy Dave" from the pub) might to have it.

Can you post a photograph of your consumer unit (CU = fuse box) and anything similar in your shed? Folks on here might be able to tell by looking at what is fitted, etc.

tldr' a safety device against electric shocks

Thanks for the quick reply!

I don't have a consumer unit in the shed. The plan was to just run an extension lead out to the shed whenever I need to use the light?

 

[pc1966]

I don't have a consumer unit in the shed. The plan was to just run an extension lead out to the shed whenever I need to use the light?

You should always have RCD protection for any mains feed going outside. Your house might already have that, but you really should check it is there.

Also it should have a self-test button that you can use to verify it really is working. That will trip out everting fed by it, so make sure everyone knows you are going to test it and that PCs are shut down, TiVo boxes not recording anything important, etc, when testing.

They should be tested roughly twice a year in most cases, but most never are

 

[MWEST85]

Thanks for the quick reply!

I don't have a consumer unit in the shed. The plan was to just run an extension lead out to the shed whenever I need to use the light?

Maybe it would be handy to see the fuse box inside my house in this case?

Thanks for the quick reply!

I don't have a consumer unit in the shed. The plan was to just run an extension lead out to the shed whenever I need to use the light?

 

[MWEST85]

You should always have RCD protection for any mains feed going outside. Your house might already have that, but you really should check it is there.

Also it should have a self-test button that you can use to verify it really is working. That will trip out everting fed by it, so make sure everyone knows you are going to test it and that PCs are shut down, TiVo boxes not recording anything important, etc, when testing.

They should be tested roughly twice a year in most cases, but most never are

Can you tell by looking at this if there is rcd protection?

 

[buzzlightyear]

yes you are good to go ,dont for get to tell some one just in case of a emergency .lol.

 

[pc1966]

Maybe it would be handy to see the fuse box inside my house in this case?

The sockets seem to be on RCD protection so that is good. However, one entry on the non-RCD side appears to say "spurs" which could be many things including odd sockets.

You can get socket testers that have a RCD test button, such as this:

TIS Socket Tester With Loop & RCD Check

A pocket sized checker for indicating loop impedance, socket polarity and RCD 30mA are all ok. Indication is by LED's and buzzer. An ideal unit for initial "checking out" of a 13A socket and will advise if the circuit is ok, needs attention, or needs urgent attention. An ideal product for...

www.toolstation.com

If you test whatever you plan of plugging the extension lead in to it will quickly tell you if it is on your protected side (power trips off) or not.

 

[pc1966]

Just to add, if you are thinking of putting in a semi-permanent extension lead make sure you use outdoor rated cable. If you can safely run it around walls/fence/etc so no trip hazard and not needing buried, you can use cable such H07RN-F rubber insulated stuff, for example:

Superlec 3CORE 1.5MM 3183P H07RN-F EPR / PCP FLEXIBLE MAINS CABLE - EN60332-1-2

H07RN-F Cable is a non armoured flexible mains and control cable designed primarily as a trailing cable for use in the supply of energy for portable or mobile equipment.The cable is Ideal for use with transformer pumps, welders grinders, temporary lighting cable and feed cables to heavy mobile...

www.superlecdirect.com

 

[MWEST85]

yes you are good to go ,dont for get to tell some one just in case of a emergency .lol.

So all I have to do is wire the live & neutral in the plug for the batten and I am safe to run an extension lead to the shed to power it?

 

[buzzlightyear]

Can you tell by looking at this if there is rcd protection

what ever you plug in to the socket for the shed push the black button in to see if the sockets dont work ,see that black button on that rcd .

 

[MWEST85]

The sockets seem to be on RCD protection so that is good. However, one entry on the non-RCD side appears to say "spurs" which could be many things including odd sockets.

You can get socket testers that have a RCD test button, such as this:

TIS Socket Tester With Loop & RCD Check

A pocket sized checker for indicating loop impedance, socket polarity and RCD 30mA are all ok. Indication is by LED's and buzzer. An ideal unit for initial "checking out" of a 13A socket and will advise if the circuit is ok, needs attention, or needs urgent attention. An ideal product for...

www.toolstation.com

If you test whatever you plan of plugging the extension lead in to it will quickly tell you if it is on your protected side (power trips off) or not.

Thank you, I will look into these socket testers just to be sure!

 

[pc1966]

So all I have to do is wire the live & neutral in the plug for the batten and I am safe to run an extension lead to the shed to power it?

Yes, but really it should have a 3A fuse for a light, and also make sure the clamp is gripping the overall white sheath of the lamp's cable.

Also please remove the paper instructions! I have seen plugs inserted for years with the paper still on

 

[MWEST85]

what ever you plug in to the socket for the shed push the black button in to see if the sockets dont work ,see that black button on that rcd .

So to clarify, If I plug my extension lead & batten into an indoor socket and press the black button should it cut the power to the socket?

 

[pc1966]

So to clarify, If I plug my extension lead & batten into an indoor socket and press the black button should it cut the power to the socket?

Yes. That button diverts 30mA of current which should be detected by the RCD causing it to trip (so all of those sockets go off).

Socket testers are a good thing to have for general checking of stuff, but they cannot be completely trusted. Basically if they say there is a fault, there definitely is. But if they say all clear it might not really be so. The one I linked to is one of the better ones, but obviously still not going to match a professionals' test equipment at around 20 times the price.