Use of 20AX switches in spurs off ring main

[redbarnman]

I bought a number of 20AX grid switches with printed labels on them e.g. washing machine. These were to put an isolator above the work top for a 13A switched socket under the work top in the utility room. Electrician says no as the spur will be off a 32A ring the switch must be capable of the ring rating not the spur (single 2.5mm2 T+E). I can almost see his point but most suppliers have a range of printed 20AX but none for 32A so you end up with an unlabelled switch or a stuck on label which is not great. Any views on this? Thanks.

 

[ferg]

Well the cable is rated @<32A

 

[Ian1981]

its 20 amp through the switch ie the max load.
Does that mean you can’t have a 13 amp fused spur?

 

[littlespark]

So what does your electrician want? 20AX gridswitch into a fused grid module to protect the spur?

What you have described is fitted in millions of homes across the uk.
Its just like having a spur off a ring, which is perfectly acceptable and within regs - (as long as its only to one point), but the spur has an isolation switch.
The only reason to have a fused spur is if theres more than one point served from the spur, ie a radial circuit off a ring

 

[Toneyz]

I bet the switch in a 13A double switched socket is not rated at 32A same principle.

 

[GeorgeCooke]

I bought a number of 20AX grid switches with printed labels on them e.g. washing machine. These were to put an isolator above the work top for a 13A switched socket under the work top in the utility room.

Why? There is no requirement for isolators above the worktop, and they look so ugly.
Also why 13a switched socket as well as an isolator, surely an unswitched socket is better if you have isolators?

The best isolation is pulling the plug. If there is a fault you will need to move the machines anyway so pulling the plug is easy.

 

[ferg]

The whole point of the isolators is to enable isolation of the appliance without moving it.

 

[GeorgeCooke]

In that case turn it off at the CU, or even the switch on the front panel.

 

[ferg]

I'm guessing the CU will be more than 2m away and the switch on the front panel does not isolate the appliance.

 

[GeorgeCooke]

So what? There is no requirement for isolators anywhere, so the CU can be used.

 

[Darkwood]

If an appliance is difficult to get out or is part of an inbuilt system then there should be a local means of isolation, this is not just for the electrical trade but others who are not so aware of the risks, the extent to this is ambiguous but with built in cookers, fridges etc it is recommended so any fault or concern electrically mean it can be safely isolated locally before removal by other trades, as an example of those not in the know how like plumbers.

 

[GeorgeCooke]

It is not a requirement or really necessary as isolation can and should be done at the CU. Local isolators are not fitted in other countries and they don't have any problems.

 

[littlespark]

"Oh no! Theres a strong burning smell coming from my washing machine.... What do I do?!!?"
"Quick, turn off the power... theres a switch marked washing machine"
"OK, got it.... Wow, that was so easy"

OR

"Oh no! Theres a strong burning smell coming from my washing machine.... What do I do?!!?"
"Quick, turn off the power... Uhhhh…. no switch? … Wheres the consumer unit!"
"Um... Its under the stairs.... behind the bucket... its in a little cupboard... You have to wiggle the latch to get the door open.. Its not got little flicky switches... just pull the fuse"
"Yeh… I think I got it.. which fuse?! Nothings marked!"
"I dunno!.... Oh no... flames!.."

Isolation switches;- Not a requirement, but damn convenient in a crisis.

 

[Midwest]

Re the argument about above worktop isolators; a lot of my customers didn't like them, so a socket in an adjoining cupboard is sufficient.

Re the OP's question; App 15 is the informative guide to spurs off RFC. Would a 20A DP switch, followed by a 13A socket could be construed as more than outlet? Done it loads myself, but perhaps thats his sparks thinking.

 

[richy3333]

It is not a requirement or really necessary as isolation can and should be done at the CU. Local isolators are not fitted in other countries and they don't have any problems.

Sorry but that’s not correct. They are required by Scottish Building Standards, so the statement isn’t actually correct.

Mandatory Standard 4
4.8.5 Access to manual controls

...Where sockets are concealed, such as to the rear of white goods in a kitchen, separate switching should be provided in an accessible position to allow appliances to be isolated.

Fixtures (sockets/switches) etc should be acted at lease 150mm above he worktop. (I've paraphrased that whole paragraph).

I appreciate you don’t have to fit them in England and Wales as far as I know? Either way it’s good practice for emergencies. I think little sparks comments are very pertinent. Do you not fit shower isolator switches in bathrooms or oven isolators in kitchens then?

To the op - if your electrician has an issue with the switches and the supply cable to the load not being protected why no incorporate a FCU module into the grid switch?

 

[Darkwood]

It is not a requirement or really necessary as isolation can and should be done at the CU. Local isolators are not fitted in other countries and they don't have any problems.

I can list you an entire manual of what they don't do in other countries as that is not really a strong argument to back your position, the reason I didn't specify a regulation is because there is no direct reference to one in the BS7671 although there is indirect regulations like following manufacturers guidelines which in reference to built in and heavy electrical appliances do recommend they are isolated before been removed be it or maintenance and replacement etc.
I do not understand your position in this debate tbh, if this is anything else in any other industry then you would need to disconnect supply before moving a machine/appliance yet you are taking the angle that this can be ignored in the realms of the domestic install.
When I was house-bashing some 20yrs ago we added a local means of isolation for large or heavy appliances if the outlet was not readily accessible and always if built in, to think you are arguing the opposite case some 2 decades later is worrying to be honest.
Following manufacturers guidelines is set into the BS7671 and has been for a while now so one should be designing install to account for the possiblilty that an appliance (if not already on site) may recommend a remote means of isolation.

Here is one of plenty of references to back up my angle on this http://www.nhbc.co.uk/Builders/Prod...uidanceDocuments/81/filedownload,65384,en.pdf

 

[Midwest]

To be fair to @GeorgeCooke, I've seen his argument posted before by many other sparks on this forum, so his opinion isn't isolated (excuse the pun )

 

[Darkwood]

@Midwest
I agree but the BS7671 then added a regulation to follow manufacturers guidelines which swung the debate from a personal choice to a recommended practice, since we don't always know what will be fitted in a unit or space then one needs to take the route of possible recommendation of the manufacturer once the appliance is bought, as for the inbuilt appliances then personally I take the view they should always have local accessible means of isolation as it can be the case that flexes get trapped under the appliance and make removing them while powered a potential for damaging the flex and also the risk of them dropping or falling over/down while been removed is also a reason to ensure they are isolated first, you shouldn't expect non trade people to start isolating full circuits to achieve this.

 

[Midwest]

@Midwest
I agree but the BS7671 then added a regulation to follow manufacturers guidelines which swung the debate from a personal choice to a recommended practice, since we don't always know what will be fitted in a unit or space then one needs to take the route of possible recommendation of the manufacturer once the appliance is bought, as for the inbuilt appliances then personally I take the view they should always have local accessible means of isolation as it can be the case that flexes get trapped under the appliance and make removing them while powered a potential for damaging the flex and also the risk of them dropping or falling over/down while been removed is also a reason to ensure they are isolated first, you shouldn't expect non trade people to start isolating full circuits to achieve this.

Easy tiger, was just saying. I prefer the socket in adjacent cupboard combo me self.

 

[SJD]

I would just add, that if you have a socket circuit with a fault, causing an RCD to trip for example, it is really handy to be able to switch off every appliance with a DP switch, to eliminate it.

Much easier than telling the customer they have to pull all the appliances out to get at the plugs.