Hi All,
Back in the olden days (70s), it was considered good practice to connect things like water heaters and washing machines using an SFCU rather than via a 13A Plug.
My new dishwasher states it shall be connected only by the supplied lead and not "Directly". I have of course ignored the instructions, cut off the moulded plug and wired it via a SFCU.
But.... What does the 17th edition have to say? Are the 70s standards still upheld? And 13 Amp plugs frowned upon?
I can't answer about the 17th edition, but you'll have a problem if the machine fails and you need to call in an engineer to fix it under warranty. There's something quite reassuring about removing the plug.
Even removing the plug in the first place might have voided the warranty, might it not?
Pointless. There is no advantage in removing the plug.
Plugs are fitted to appliances deemed to be portable. Fixed appliances usually have a switch.
The easiest way of dealing with that is to fit a training socket to the FCU.
Our kitchen was fitted professionally, all 'signed off' to Part P etc. and included a fitted dishwasher etc. It has a 13A plug to a socket. As do the fridge and freeze (separate items). The hob, and main oven, and a second 'combi' oven each have a 'radial' to the consumer unit.
A washing machine I would not usually bother hard wiring unless installing in a location like a bathroom where a plug may not be permitted.
It does not have anything new to say that I am aware of...
Plugs are fine generally. Although if you have a "full load" appliance with a long duty cycle (say an immersion heater), then a FCU would be better, since there is less chance that it will get hot as a result of connection contact resistance.
Also keep in mind that many double sockets are only rated at a continuous load of 20A, so two 13A loads should not usually be placed on the same double socket.
ISTR The problem arises when the washing machine is in a room with s shower.
I presume diversity makes that fine. And FWIW I've never known a square pin double kitchen socket feeding high power appliances get hot.
NT
A shower should have its own, dedicated, supply.
As for a washing machine in the same room, what about the 'zone' rules?
That's why you may not be able to have a socket outlet in the same room.
At one time I was running 3 kW immersion heaters for about 12 hours at a time through 13 amp plugs and sockets (light industrial application). Although I was using MK plugs and MK (switched) sockets in metal boxes, they did sometimes "cook", I guess perhaps when the screws holding the wires loosened. Since moving over to the industrial type 16 Amp unswitched round plugs and sockets there has been no problem. Down the line, these are wired up with lever type WAGO connectors, and so far these are holding up fine too.
You can now (as from the 17th edition) have a socket in a shower or bathroom - however the minimum distance from the furthest extent of zone
1 is set at 3m, so only large rooms need apply.
It would need to be located outside the zones (i.e. beyond zone 2). That could be as little as 600mm from the bath for example.
However there is still a general requirement that the appliance be appropriate for the location in question, so if particularly steamy or in danger of getting splashed, then it still may not be appropriate.
My 2-yo washing machine is only 2.2kW at most, so less than the old one (about 2.9kW IIRC). Do you wire your 3kW kettle to an SFCU?
t things like water heaters and washing machines using an SFCU rather than via a 13A Plug.
d and not "Directly". I have of course ignored the instructions, cut off t he moulded plug and wired it via a SFCU.
still upheld? And 13 Amp plugs frowned upon?
Hmmm...... I don't know the rating of my kettle off hand, but a similar on e on Tesco.com is Power - 3 (I assume that is Tesco Speak for 3KW!). I don 't have mine on a SFCU (though I have seen it done), but then I don't leave it running for 3 hours unattended.
Another poster suggested plugging the dishwasher into a trailing socket, I did this once with a Tumble drier, and when I moved house I had to chop the plug of the tumble drier as there was no way to separate it from the trail ing socket (actually a 4 way).
See this:
The black plug is a moulded one, supplied with the appliance (3Kw oven), the orange one (A B&Q "heavy duty" plug) is one I fitted to another 3Kw oven (which was running off another outlet with similar heat damage to the one shown. I should have photographed the fuse areas, but there was a lot of heat damage there which I think has conducted down the live pin to the socket. (Although hard to tell as heat could have originated in the pin and traveled both ways)
Gordon
For the live pin, there are five places (per pin) where you can get high contact resistance. In my experience, one of the most common (especially for the cheap four way "spreaders", which I never use for kilowatt loads) is between the pin and the sprung "horseshoe" in the socket. Then there are the two screw terminals where the wires are connected. Then the two ends of the fuse (for the live pin). It is often evident by inspection which has failed. It is sometimes difficult to differentiate between the pin-fuse, and the pin-socket because of heat conduction through the brass pin. When you have a burn mark on the socket or a melted sleeve pin (as in the photo) it is almost certainly one of these two sites.
I believe that this 3m rule was also to clarify the situation in bedrooms that have had baths or showers fitted for disabled persons.
Interesting.
I like the theory that the heat was conducted on the pin and travelled into the plug That is consistent with my finding of burnt plugs and sockets.
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