Should a ring main be fused??

[Antisme]

Hi, I wonder if you could help me.

We have a house from the 60's that as far as I know has never been rewired or altered as the fuse box is still an original one that you have to replace the wire if the fuse blows and also looks like it belongs in a museum..

Now last night my son fell off his bed and hit his head so hard off a flush fitting double socket that he had to go to hospital and also smashed the outer plastic casing of said socket. So today I went to replace this and thought instead of killing all the house hold power I would just pull the fuse and change it that way.

With things plugged into all the sockets in the house I got my wife to check as I pulled each fuse out and to my amazement when I pulled out the last one none of the sockets in the house had gone off. Now, I'm pretty certain that it does not have a rcd/mcb as it is very old and only has one switch on it which is the main master on off switch.

So I would like to know is this normal and if not could anyone please explain why it may be like this?

Hope someone can help

Ant

 

[riveralt]

How do you know that the sockets are live?

Are the sockets still live when you turn the main fusebox switch off?
If they are then you either have another source of power or someone has wired the ring main directly into the incoming terminals of the main switch.
If none of the fuses are in place and the sockets lose power when the main switch is off then they could have put your ring main cables in the CU side of the main switch.

 

[canduit]

Or, if the OP pulled out and replaced each fuse one-by-one during the 'test', then each leg of the ring could be supplied by 2 different fuses.

 

[Antisme]

The sockets are still live when I removed all the fuses as I had various items plugged into them but once i turned the master switch off everything went dead in the whole house..

Hope this helps

 

[sparkybird]

Sounds like you need to get an electrician in to look at this - perhaps someone's been messing with the electrics and there may be other problems too.
Better safe than sorry

 

[Antisme]

Or, if the OP pulled out and replaced each fuse one-by-one during the 'test', then each leg of the ring could be supplied by 2 different fuses.

You have hit the nail on the head.

When i was removing the fuses I did this one by one so as not to place the wrong one back in a different slot but having done another test with all fuses removed the sockets stopped working

Thank you very much.

Just out of interest does anyone know how common this system is or is our house just "special"

Once again thanks everyone

Ant

 

[canduit]

This system is not correct. I would recommend that you get a PIR - Periodic Inspection Report from a competent & reputable electrician. Lord knows what else could be lurking. And we hope your son gets better soon.

 

[OwainDIYer]

It's possible that 2 x 15A radials were 'converted' to a ring in about 1947 by joining the ends together and fitting 13A sockets.

 

[ericmark]

If your fuses are 15A then maybe OK. If 30A then needs changing.

 

[wingcoax]

It's possible that 2 x 15A radials were 'converted' to a ring in about 1947 by joining the ends together and fitting 13A sockets.

I think you may just have hit the proverbial nail. Are the sockets mounted on the skirting boards or are there signs that they have been? Probably they may have been raised at some time.

 

[333rocky333]

If your fuses are 15A then maybe OK. If 30A then needs changing.

If two fuses are supplying one circuit then the size of the fuse is irrelovant
and needs investigating

Put in then remove each fuse in one at a time to see which and how many positions liven up the same circuit, if the same circuit does liven up from two seperate fuse positions, then you will have confirmed a problem

Use the main switch each time to isolate before removing and inserting the fuses

 

[EFLImpudence]

If two fuses are supplying one circuit then the size of the fuse is irrelovant
and needs investigating.

May not be ideal, but surely a ring with 15A fuse on each leg is actually safer than one with 30A fuse covering both.

 

[JohnW2]

May not be ideal, but surely a ring with 15A fuse on each leg is actually safer than one with 30A fuse covering both.

Indeed it is, in terms of cable protection; in fact, I've often pondered why this did not appear as a requirement when ring finals were introduced.

The main safety concern would be that we are very much not used to the concept of having to remove two fuses (or switch two MCBs/RCBOs) in order to de-energise a single circuit - and this would undoubtedly result in some dangerous incidents, particularly at the hands of householders, DIYers etc.

Kind Regards, John.

 

[EFLImpudence]

The main safety concern would be that we are very much not used to the concept of having to remove two fuses (or switch two MCBs/RCBOs) in order to de-energise a single circuit - and this would undoubtedly result in some dangerous incidents, particularly at the hands of householders, DIYers etc.

Good point.

 

[333rocky333]

I recall seeing a badly terminated cable in a fuse once removed it to strip it and found it to be live, although we should test it I know, but i would say a lot of us would not test an outgoing single cable from a fuseway.