This discussion is locked.

You cannot post a reply to this discussion. If you have a question start a new discussion

Grid switch ratings enquiry

Had an interesting chat with a tech dept this afternoon after coming across some grid switches in a domestic kitchen.

Four grid switches (sharing a common backbox) are each fed via their own 16A cb's, and each feeds 1G sockets (for a cooker hood, fridge freezer, etc). Ignoring the cable sizes (the focus being on the grid switches), given the 13A plug fuses limits the loads in each cct, would you have the current rating of the grid switches equal to or higher than the 16A cb's (e.g. 20A), or lower (but equal to or higher than the socket rating e.g. 13A/14A)?

F

Parents

0 Zoomup over 5 years ago

AJJewsbury:

Presumably the single 13 Amp sockets are behind the appliances like the fridge freezer, or at high level above the extractor hood, so are very unlikely to be used for additional appliances. That is why there are conveniently positioned grid control switches. Therefore this is a non-issue. A 10 Amp grid switch will not catch fire or blow up if carrying 11 Amps in most cases. A 20 Amp grid switch will be fine for other appliances like washing machines or tumble driers etc. Overloading is very unlikely if the single 13 Amp sockets are inaccessible. Stop worrying needlessly.

Ah, but you're only considering overload - what about fault currents?

- Andy.

Relating to the original post, I can not see how a cooker extraction hood or a fridge freezer can in any way cause a 20 Amp sustained current to flow through a grid switch for hours. The extractor will no doubt be fused at 3 or 5 Amps. The fridge freezer can not do so also. If the makers of the fridge freezer consider a 13 Amp fuse good enough to protect its flex then who am I to disagree?

The other two appliances are unknown, they could be a hob and oven. Both can not by design each cause an overload of a 20A value under healthy or fault conditions. Also don't forget the R.C.D. protection.

Anyway 20 Amp grid switches will cover that scenario.

Z.
Cancel
Vote Up 0 Vote Down

Cancel

Reply

0 Zoomup over 5 years ago

AJJewsbury:

Presumably the single 13 Amp sockets are behind the appliances like the fridge freezer, or at high level above the extractor hood, so are very unlikely to be used for additional appliances. That is why there are conveniently positioned grid control switches. Therefore this is a non-issue. A 10 Amp grid switch will not catch fire or blow up if carrying 11 Amps in most cases. A 20 Amp grid switch will be fine for other appliances like washing machines or tumble driers etc. Overloading is very unlikely if the single 13 Amp sockets are inaccessible. Stop worrying needlessly.

Ah, but you're only considering overload - what about fault currents?

- Andy.

Relating to the original post, I can not see how a cooker extraction hood or a fridge freezer can in any way cause a 20 Amp sustained current to flow through a grid switch for hours. The extractor will no doubt be fused at 3 or 5 Amps. The fridge freezer can not do so also. If the makers of the fridge freezer consider a 13 Amp fuse good enough to protect its flex then who am I to disagree?

The other two appliances are unknown, they could be a hob and oven. Both can not by design each cause an overload of a 20A value under healthy or fault conditions. Also don't forget the R.C.D. protection.

Anyway 20 Amp grid switches will cover that scenario.

Z.
Cancel
Vote Up 0 Vote Down

Cancel

Children

No Data

Grid switch ratings enquiry

Community Rules & Guidelines