Dealing with an overloaded circuit

[assegayer]

hi guys another query.

say a customer had a overloaded circuit where it was just down to pure ****e design, how would an electrician deal with this. I could only think of a rewire of that circuit as the only viable option. as off course u cannot just upgrade the protective device.

i ask because i have a mate living in a single room and when he puts the kettle on after a little while 'flick' the breaker is off, now i havnt seen the job but i have a feeling the socket circuit in his room is joined with other rooms thus accumlative overload. (off course these are all assumptions as havnt seen yet)

 

[telectrix]

could also be an under sized or a "tired" MCB.

 

[Darkwood]

Does he have electric heaters plugged on the ring etc ...is the kettle faulty and only shows when the element is hot ...without been hands on here its all guess work.

 

[davesparks]

It depends how significant the overload is, and the accessibility of the wiring.
You can either reduce the load, or split the circuit into two.
If it's a ring you might get away with splitting it in half and making it two 20A radials (unlikely)
Or you could run 2x 2.5 to an accessible point somewhere near the middle of the ring and split it into two rings.

 

[assegayer]

Does he have electric heaters plugged on the ring etc ...is the kettle faulty and only shows when the element is hot ...without been hands on here its all guess work.

I can definitely wipe that fault out of the way as he said when he plugs the kettle on the shared kitchen socket it works fine, but he doesnt always want to go to the kitchen (for privacy off course)

 

[Richard Burns]

As he is living in a single room, if the house is specifically wired, I would suggest that the circuit is designed as a 16A (or maybe even 10A) radial for that room and that other loads in the room are taking the breaker over the overload limit of the breaker.

This is one of the methods used for limiting current draw in multi occupancy houses.

 

[assegayer]

As he is living in a single room, if the house is specifically wired, I would suggest that the circuit is designed as a 16A (or maybe even 10A) radial for that room and that other loads in the room are taking the breaker over the overload limit of the breaker.

This is one of the methods used for limiting current draw in multi occupancy houses.

so how would you go about sort this problem out.

 

[davesparks]

so how would you go about sort this problem out.

Get a lower powered kettle

 

[assegayer]

Get a lower powered kettle

in this situation he probably will, but say just for knowledge if somebody just wanted it to work without getting a lower wattage kettle, all i could thing of is either rewiring the circuit, or spuring of another appropriate circuit (with appropriate fusing off course if required)

 

[assegayer]

lol forgot to say, before another 'so called sparks' came to check the problem out and he had but a small link of cable in the fuse board between the feed and load side of the mcb, so rendering the mcb useless so the kettle worked. however after the landlord was doing some refurbishments and another spark came by and removed the link and said its not safe, but did not attempt to solve the problem.

 

[davesparks]

in this situation he probably will, but say just for knowledge if somebody just wanted it to work without getting a lower wattage kettle, all i could thing of is either rewiring the circuit, or spuring of another appropriate circuit (with appropriate fusing off course if required)

If it is tripping because the circuit has been restricted to a specific size deliberately to prevent the total load of the installation overloading the incoming supply then there is nothing to solve!

 

[assegayer]

If it is tripping because the circuit has been restricted to a specific size deliberately to prevent the total load of the installation overloading the incoming supply then there is nothing to solve!

my poor wording, say it was a poorly designed circuit the supply can off course take it, its an 80 amp supply mate, with a 20amp radial, forget the situation with my mate now. im just giving an example if it was with someone else who wants to be able to put a kettle or any appliance with that load on

 

[davesparks]

See post 4

 

[assegayer]

appreciate your time mate

 

[Richard Burns]

If you are considering the general case of a circuit with a low rating breaker that does not meet the requirements of the load applied, then the resolution would depend on the way the circuit has been installed.

If the cable were 1.5mm² T&E on a 16A breaker if the conditions of installation were perfect then you may be able to take the breaker up to 20A, however this would require careful consideration as the only method allowing 20A CCC is clipped direct (or free air) with no other derating factors.

If the circuit were for some reason installed with 4mm² singes in conduit then you may be able to raise the breaker to 32A in good conditions.
However these are best case scenarios and due consideration of all relevant factors would need to be taken into account.

There is no one simple answer but I would point out that the majority of circuits (with possibly less emphasis in domestic circuits) are designed at the time of installation to just meet the minimum requirements because this is the most cost effective method of installation and cost is often an overriding factor. This being the case there may well be no leeway available to make changes to the capacity of a circuit without rewiring the circuit.