Number of Outlet in One Circuit As Per IEC

Doesn't it depend on the cable configuration?

• Under British Standard 7671, a 2.5mm² cable can be run to any number of 13A sockets in a radial provided the breaker is 20A. However, it becomes a better idea to form a ring with the 2.5mm² up to 100m² floor area using a 32A breaker. There is no practical limit to the number of sockets that can be added to the 32A ring however the number of spurs off the ring must not be greater than the number of sockets on the ring.

Nowadays at homes/offices from each socket they feed a power strip or multi-plug to supply more than a single item like computer,monitor,printer etc thus creating loose connections. If we replace single sockets with multiple(2 or 3) would it be saver?. Also when we wire two 5Amp sockets from a MCB rated 10Amp and if only a small appliance rated around 3Amp is used will the fuse protect(OC/EF) the appliance?.

Bad practice and dangerous. Speaking with a UK hat on a combi block with its 13A fuse fitted to the plug is electrically protected against overload. The problem is that most of the electronic kit has a front end filter circuit. This filter circuit retains a small charge of electricity. When you 3 or 4 of these all plugged into a combi block and then 1 combi block plugged into another this small charge builds up so that if you unplug the first combi block and touch the pins you can get a shock. (UK system now demands a high integrity earth system on sockets for computers)

Replacing a single socket with a twin or triple is good.

The fuse/breaker is not intended to protect the appliance. If you overload the circuit by plugging too many appliances in the breaker should trip. If you short an appliance cable out the breaker should trip.

You can only EF with an RCD.

OC is provided by a device of appropriate size. A 3A socket would be a 3A fuse.

Fuses and breakers are there to protect the cable.

you can connect all that you want, as long as the current does not pass the 20 amps!

As the guys have said the regs don't impose a limit on the number of sockets. You must put your engineers hat and do some design work. In theory you could have all of the electrical equipment from a single circuit. (assuming all protective devices etc in place.) One trip though and the whole lots goes off. We split things generally into lighting circuits and small power. In house its usual to have a ring main circuit upstairs and another for downstairs. Do the sums though if the sockets in the kitchen are feeding a washing machine, tumble drier, dish washer and small oven its electrically full. In a situation like this you would use a ring main just for the kitchen. Now look at your sockets. What sort of use are they going to have. In a computer suite and more so where RCDs are used you might have 4 sockets from a breaker. In a village hall where there is light use you might have 24 sockets from a breaker. The 20 or 32A breaker protects the ring or radial circuit and in the case of the UK plugs a 13A plug top fuse will clear first.

so the standards allow us to use unlimited number of socket but still we need to check if the breaker that has been used can still hold the actual full load current. thanks..

As always, it is the cable that needs to be protected against overload.

Bascially yes.

In the UK there are several different configurations, radial circuits and then our infamous ring. Nominally a ring can cover a floor area of 100m². From memory the IEC circuits are radial and are protected back at the DB i.e. no fuse in the plug. The answer is at 5A a socket you could have 4 sockets i.e. 20A and at 10A per socket you could have 2 sockets. You need to look at your own application and the bottom line is to provide a safe system free of nuisance trips. Try and find outr what sort of load you could expect from each socket. Remember if you do take multitple circuits away from the DB you need to apply a cable derate (I.E.E. regs)

In the I.E.E regs we look at diversification when we apply for a supply. Sizing an incomer you wouldn't expect every circuit to be fully loaded although you must expect every circuit to be able to carry full load safely if called upon.

Hi ,

in IEC 60-364 ( installation rules) , there is no specific mention on the number of socket outlets that can be connected on one circuit.

In the national installation rules, there may be some extra specifications.

In the French NFC15-100, which is the local code based on IEC 60-364 , there is an additional regulation that specifies a maximum number of 8 socket outlets downstream a circuit breaker.