Hello,

I've been pondering something for a few days and was hoping someone
here could help. Please forgive me if any of the following is wrong.

The maximum load on a normal ring circuit for sockets is 32A. Lets
assume that this circuit is fully loaded, there are appliances plugged
in that are drawing a total of 32A.

Now each socket on this ring is rated as 13A, at least that is what it
says on the back of the spare sockets I have. (13A 250V). They will
probably cope with a bit more though.

So my question is, as the circuit is fully loaded does this mean that
each socket on the ring have 32A "flowing" through it? If so will they
catch fire or melt?

A similar question is lets say we have a 13A socket spurred off a 13A
socket. Both sockets are fully loaded, does this mean that the first
socket has 26A "flowing" through it? Will it catch fire or melt?

Thanks

Graham

Graham Jones wrote:
Hello,

I've been pondering something for a few days and was hoping someone
here could help. Please forgive me if any of the following is wrong.

The maximum load on a normal ring circuit for sockets is 32A. Lets
assume that this circuit is fully loaded, there are appliances plugged
in that are drawing a total of 32A.

Now each socket on this ring is rated as 13A, at least that is what it
says on the back of the spare sockets I have. (13A 250V). They will
probably cope with a bit more though.

Maybe, maybe not. The 13A is specified as the minimum capacity, and
cheap plug/ socket pairs will often only just carry it within the
specified rise in temperature. Some illegal imports won't even do that.

So my question is, as the circuit is fully loaded does this mean that
each socket on the ring have 32A "flowing" through it? If so will they
catch fire or melt?

No, partly because the current flowing in the ring main is split (in
theory, assuming no faults) into 2 x 16A parts, one coming to each
socket from each direction, so in theory, the connections at the rear of
the socket are carrying no more than 16A, unless it's a double, in which
case they may be carrying 26A. Also, the connections at the rear of the
socket are capable of carrying more current than the contacts, and
*should* be rated to carry the full 32A without overheating.

A similar question is lets say we have a 13A socket spurred off a 13A
socket. Both sockets are fully loaded, does this mean that the first
socket has 26A "flowing" through it? Will it catch fire or melt?

Not if the connections are sound. Loose screws on the connections can
cause dangerous overheating as can other installation problems, not
forgetting that the spring contacts inside the socket can weaken over time.

--
Tciao for Now!

John.

On Feb 17, 3:22*pm, Graham Jones wrote:
Hello,

I've been pondering something for a few days and was hoping someone
here could help. Please forgive me if any of the following is wrong.

The maximum load on a normal ring circuit for sockets is 32A. Lets
assume that this circuit is fully loaded, there are appliances plugged
in that are drawing a total of 32A.

Now each socket on this ring is rated as 13A, at least that is what it
says on the back of the spare sockets I have. (13A 250V). They will
probably cope with a bit more though.

So my question is, as the circuit is fully loaded does this mean that
each socket on the ring have 32A "flowing" through it? If so will they
catch fire or melt?

A similar question is lets say we have a 13A socket spurred off a 13A
socket. Both sockets are fully loaded, does this mean that the first
socket has 26A "flowing" through it? Will it catch fire or melt?

Thanks

Graham

The only current "through" the socket is that to the load that is
plugged in.

The two connections for the ring (or spur) go into the same screw
terminal on the back of the socket. The total current in the ring
stays in the ring, it doesn't go into the socket and back out again.

MBQ

On Feb 17, 3:22*pm, Graham Jones wrote:
Hello,

I've been pondering something for a few days and was hoping someone
here could help. Please forgive me if any of the following is wrong.

The maximum load on a normal ring circuit for sockets is 32A. Lets
assume that this circuit is fully loaded, there are appliances plugged
in that are drawing a total of 32A.

Now each socket on this ring is rated as 13A, at least that is what it
says on the back of the spare sockets I have. (13A 250V). They will
probably cope with a bit more though.

So my question is, as the circuit is fully loaded does this mean that
each socket on the ring have 32A "flowing" through it? If so will they
catch fire or melt?

A similar question is lets say we have a 13A socket spurred off a 13A
socket. Both sockets are fully loaded, does this mean that the first
socket has 26A "flowing" through it? Will it catch fire or melt?

Thanks

Graham

Thanks for the replies, I was missing the fact that the contacts can
carry more than the rest of the socket. It makes sense now.

On 17/02/2012 15:22, Graham Jones wrote:
Hello,

I've been pondering something for a few days and was hoping someone
here could help. Please forgive me if any of the following is wrong.

The maximum load on a normal ring circuit for sockets is 32A. Lets
assume that this circuit is fully loaded, there are appliances plugged
in that are drawing a total of 32A.

Now each socket on this ring is rated as 13A, at least that is what it

13A for a single, 20A for a double...

says on the back of the spare sockets I have. (13A 250V). They will
probably cope with a bit more though.

Depends on the quality of the socket and for how long...

So my question is, as the circuit is fully loaded does this mean that
each socket on the ring have 32A "flowing" through it? If so will they
catch fire or melt?

No and no. If there is nothing plugged into the socket, then there will
be no current drawn through it. The wires of the circuit may pass
"through" the socket in the sense that they join at its terminals, but
this current will not be flowing through the socket itself.

Also note in the case of a ring circuit, only some of the total current
will be running past each socket, since there are two alternate cable
routes to each socket.

A similar question is lets say we have a 13A socket spurred off a 13A
socket. Both sockets are fully loaded, does this mean that the first
socket has 26A "flowing" through it? Will it catch fire or melt?

Again no, because the spur is not plugged into the first socket, but
connected directly to the cables feeding the socket instead. They are
capable of carrying the full circuit current and some more typically.

--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

On 17/02/2012 15:53, Graham Jones wrote:
On Feb 17, 3:22 pm, Graham wrote:
Hello,

I've been pondering something for a few days and was hoping someone
here could help. Please forgive me if any of the following is wrong.

The maximum load on a normal ring circuit for sockets is 32A. Lets
assume that this circuit is fully loaded, there are appliances plugged
in that are drawing a total of 32A.

Now each socket on this ring is rated as 13A, at least that is what it
says on the back of the spare sockets I have. (13A 250V). They will
probably cope with a bit more though.

So my question is, as the circuit is fully loaded does this mean that
each socket on the ring have 32A "flowing" through it? If so will they
catch fire or melt?

A similar question is lets say we have a 13A socket spurred off a 13A
socket. Both sockets are fully loaded, does this mean that the first
socket has 26A "flowing" through it? Will it catch fire or melt?

Thanks

Graham

Thanks for the replies, I was missing the fact that the contacts can
carry more than the rest of the socket. It makes sense now.

If you think about it, the contacts are actually clamping a pair of
wires together - chances are the joint would carry full circuit current
even if the terminals themselves were actually insulating.

--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

On 17/02/2012 15:41, John Williamson wrote:

No, partly because the current flowing in the ring main is split (in
theory, assuming no faults) into 2 x 16A parts, one coming to each
socket from each direction

I'm going from a different theory to you - and no knowledge of what part
P says.

If the socket is near one end of the ring the resistance in the wires in
the two directions will be very different, and most of the current will
come from one direction.

As others have pointed out this probably doesn't matter.

Andy