Washing Machine Isolator Switch

[Savo]

Hello,

I am hoping that someone may be able to help me. I have searched this site but not been able to find anything relating to this topic.

I have a washing machine at home, fitted with a 13a fuse, which plugs into a standard wall socket. As the machine is under the worktop, there is an isolator switch above the worktop to allow the socket to be switched off easily. I am currently replacing the existing plastic sockets with stainless steel ones to match the rest of the kitchen, however, when I removed the existing isolator switch, it appears to be a 20a switch. The reason for the query is that I need to know whether to replace the switch with a similar rated switch, or if the I should be using a lower rated switch given that the washing machine is only a 13a fuse. Any advice would be much appreciated as this is the only switch left in the kitchen that has not been replaced and I'm wary about replacing it until I know that I am using the right switch.

Thanks in advance for any help.

Regards,

Ian

 

[JohnD]

The method you are already using is correct.

 

[Savo]

Hi John,

Thanks for the quick reply. Just out of curiosity, is there any reason why the isolator has to be a higher rating than the socket itself?

Thanks again for your help.

Ian

 

[JohnD]

DP switches are made in 20A (and higher)

Sometimes they are used to control a 20A appliance; sometimes they are used to control a double socket which is not expected to have a combined load above 20A.

I suppose they could make a slightly cheaper one at 13A as well, but they don't. there is a FCU at 13A which includes its own fuse but this is not as suitable (IMO) for what you are doing. In your situation, if there is a fault leading to an overload, the 13A fuse in the plug will blow. You don't want two 13A fuses on the same appliance.

 

[Savo]

Hi John,

Thanks very much for your help. I have seen 13a isolator switches (with the neon indicator light on), but having read your comments, I'll get one of the 20a switches to be on the safe side.

Thanks again,

Ian

 

[fattony]

Hold on, I always believed that a fixed appliance, e.g washing machine, dishwasher should be plugged in low level with a switched spur with neon above te worktop controlling the socket below.

Is using a 20A double pole switch isolator just your prefrence?

 

[JohnD]

A switched fused spur and a fused plug gives you two 13A fuses per appliance; the ideal number is one.

You can use a FCU and a flex outlet, but this makes it more difficullt to unplug the appliance for servicing or replacement. I have heard the suggestion of using an FCU and an unfused 15A round pin plug, but most people are not used to these (householders, younger electricians and appliance repairmen) and might be puzzled or confused to find one.

I think the above-counter DP switch and the fused plug below is ideal.

 

[Adam_151]

Heres one for you if you want to be anal about different standards and such... 20A DP switch with supply side directly on ring, from a standards and regs POV, alllowed or not?

 

[RF Lighting]

I agree about not having two fuses in line, although I can't see it being a major problem apart from being annoying in tracing which fuse has gone if a fault occurs. If you are bothered about having a neon then you could fit a 20A DP switch with a neon, but as far as I am aware the neon is not required, and IMHO not necessary.

 

[JohnD]

Heres one for you if you want to be anal about different standards and such... 20A DP switch with supply side directly on ring, from a standards and regs POV, alllowed or not?

It's the load that matters. The switch is just a switch.

 

[RF Lighting]

Heres one for you if you want to be anal about different standards and such... 20A DP switch with supply side directly on ring, from a standards and regs POV, alllowed or not?

I don't see why not. The socket below the worktop is in essence a spur from the ring, which is perfectly acceptable, providing the load side of the DP switch only feeds ONE socket.

 

[Adam_151]

I was kinda getting at whether or not the terminals on the load side were suitable for joining the ring, if they are only rated at 20A, like you wouldn't pick a 20A JB for the job...

stole the idea from here: http://www.theiet.org/Forums/forum/messageview.cfm?catid=205&threadid=10148&highlight_key=y

 

[RF Lighting]

You mean supply side surely?

A 13A single socket is only rated at 13A but you can join a ring in that.

 

[JohnD]

I was kinda getting at whether or not the terminals on the load side were suitable for joining the ring, if they are only rated at 20A, like you wouldn't pick a 20A JB for the job...

stole the idea from here: http://www.theiet.org/Forums/forum/messageview.cfm?catid=205&threadid=10148&highlight_key=y[/QUOTE]
I agree with the guy who said

"once the joint is made and, as long as the terminals are of sufficient physical size and tightened properly they become surplus to requirements. The cores being compacted together are to all intents and purposes one.
Second point, the 20A rating refers to the contacts within the switch not to the terminals. "

 

[Adam_151]

You mean supply side surely?

Yes, thats what I intended to type

for the 13A socket, I'm lead to beleive that BS1363 says that the terminals have to be suitable for putting on a ring circuit...

I agree its *much* more of a standards issue than a real life issue, and I'd eat a paper hat or something if a properly terminated 20DP overheated from being used this way, just thought it was an interesting angle that had been brought up there