Is it possible to get a 16A fused spur, or components to make one up?
My new tumble dryer has arrived. It obviously has two heating elements (or less likely, some complicated power electronics), as it can be configured for 10A or 16A operation. It is currently plugged into a 13A socket switched by a 20DP switch on a 32A radial, so must be run at 10A. Drying times would be considerably reduced using the 16A option, which given the avalanche of washing it deals with, would be very useful.
Diversity in the circuit is easily sufficient for the load at 16A. Has anyone seen some sort of replacement for a 13A unswitched socket that would enable me to connect it in? It needs to be protected at 16A via fuse or MCB, I'm quite happy to hard wire the flex into it, or a nearby junction box. I have neither the money, space or inclination to install a 1 way consumer unit with a 16A MCB. Something that fits in a single electrical box and doesn't jut out from the wall would be good.
You could use a 16A industrial outlet, but this must be protected at no more than 20A, IIRC. However, it won't meet your criteria of fitting a standard electrical box.
It is providing the 16A protection that is the issue. I'm quite happy wiring the flex into a 20A junction box rather than a plug/socket arrangement.
What is the lowest profile 16A fuse or MCB enclosure that is available? I have plenty of wall space, but it can't jut out more than a couple of centimetres, so I can't use a consumer unit. In fact, MCBs are so thick, I doubt any enclosure could be made to fit. Presumably it isn't possible to get BS1362 16A fuses? I don't want to run yet another circuit back to a dedicated 16A circuit, especially as I have enough power available through the current circuit.
"Christian McArdle" wrote | Is it possible to get a 16A fused spur, or components to make one up? | My new tumble dryer has arrived. ... plugged into a 13A socket switched | by a 20DP switch on a 32A radial, so must be run at 10A. Drying times would | be considerably reduced using the 16A option, | It needs to be protected at 16A via fuse or MCB,
AIUI normal practice would be to use a 16A BS4343 socket on a 20A radial. If the tumble is happy to be fused at 20A and the circuit would still remain adequate for the other loads, could you drop the circuit MCB to 20A? especially if you were careful to switch off the dryer for the few minutes whilst the washer was filling and heating the wash water.
A 16A breaker would be better. However, I only have 2cm thickness behind the dryer to work with. I can't see any consumer unit fitting in there. I can flush in small items, like wiring accessories.
The BS4343 industrial-style plug and socket is the solution which springs first to my mind. Some jutting-from-wall is inevitable, though you can reduce it with a right-angled plug (RS 491-591) and a small-flange socket (RS 488-983), sinking the enclosure (RS 502-045 or non-flammable box of your own devising) maximally into the wall. With this range of plugs and sockets there'd be no question of the contacts being stressed by repeated pulling of the full load.
Neater alternatives, still rated for 16A (though some provide less complete confidence in contact integrity for long-term use at these high-for-domestic-appliances loads) include: the IEC "higher current" style fittings (RS 295-8743 socket, 295-8771) (sometimes seen on higher-power 19inch rack power distribution units); the ST18 connectors, used on Aphel mains-distribution units (RS 235-565 plug, 213-4650 socket)
- these don't latch massively strongly - and even the HVAC-style (heating-ventilation-and-aircon) connectors like the RS 155-9496 flat-to-the-wall socket with mating plug 103-0967. Oh, and there are the Neutrik Powercon mains connectors: RS 246-8284 for the plug,
246-8313 for the socket; these latter rated at 20A (assuming a 2.5mmsq flex, they say: not often seen on UK appliances, but a lot more widely available than hen's teeth or rocking-horse droppings; cut lengths from a trade counter, often disguised as 'Arctic' cable ;-).
That's the connector side of things - alternatives abound. Now, what about overcurrent and short-circuit protection? What you'll have with any of the above - or, indeed, hard-wiring direct into the 20A switch - is a dedicated socket into which only your timble dryer can connect, so there's no chance of an overload from multiple appliances sharing the socket. Is the tumble-drier a load which can itself produce an overload? I wouldn't have thought so: its motor is a small device not responsible for most of the consumption, and if the drum gets stuck, you'll presumably have a slipping belt and possibly internal overload protection rather than a sustained current of say 40A (a figure chosen to be high enough to make the appliance cable dangerously hot, but too low to trip your 32A MCB). And with a short flex, it's unlikely (but you could do the calcs to be sure!) that the earth loop impedance will be too high to give you acceptable disconnection times. Without doing the calculations it's not possible to be certain, but I'm far from convinced that you need closer overcurrent protection for this appliance-and-flex (especially if it is, or can readily and safely be made, a 2.5mmsq flex).
If, however, you're determined to add a 16A or 20A overcurrent protection element, RS will be happy to sell you either a "simple" fuseholder for 6x32mm fuses - fuseholder 236-5731 rated to 16A, pack of 10 16A fuses to fit at 209-9298 or 209-9311 for Aunty Serge; or a 1-2 module DIN rail enclosure and a 16A MCB (doesn't have to be physically right next to your plug-n-socket, though you did say you really don't fancy such a 1-way mini-CU solution); or even a CBE (a Circuit Breaker For Equipment - different from an MCB in being rated for much smaller short-circuit currents, but fine used in conjunction with the MCB you already have on the ring circuit). For example, there's a thermally-operated 15A CBE as stock number
405-9157, or a 20A cousin at 405-9179, under 6 quid + VAT, or in pretty rocker-switch style - 286-0719, 16A, or 286-0753 if you want an Illuminated one. These last are double-pole switching, so could sensibly replace your existing 20A switch and provide isolation for maintenance as well as overload protection.
Hope that gives you some useful ideas for your next visit to rswww.com ;-)
How big is it? Most switchfuses are several times the size of what I'm looking for. Totally unnecessarily large, it has to be said, given that it is a glorified fuse holder.
P.S. Can I just use an mains inline fuse holder housed in a flush electrical box? I see there are plenty of 16A HRC fuses around in numerous sizes rated nominally at 400V. I would just need to find a suitably rated holder for a C-20 or 831 size cartridge fuse.
Well, despite your reasoned suggestion that overcurrent protection may be met safely by a B32A MCB, the instructions state that protection for overcurrent must be provided for 16A, and I suspect the wiring regulations will expect you to follow specific manufacturer's instructions. I'll look again, just in case 20A will be allowable, which allows a better choice of protection if old "UK" style ratings are used.
This is the direction I appear to be moving in. The load is mostly resistive, I'd imagine. Can't imagine the motor is particularly powerful. It's not like it is 1600 spin, like its room mate. In fact, with 1600 spin and the 16A upgrade, the washing machine should become the slowest link in the chain when it comes to cycling through the washing. (Often have 3 or 4 loads to pass through in a day and have to sit around waiting for the dryer to finish, particularly if quick wash is used).
Will investigate. Sounds intriguing.
The current switch is a pretty 3 gang grid switch above worktop level also shared with dishwasher and washing machine. Definitely a "want to keep" situation for aesthetic reasons. All 3 items are off a single 6mm T&E B32A radial shared with nowt else. Should be plenty of diversity to be found to keep the lot happy. After all, I've seen houses with a single 32A ring running that lot, plus TV, microwave, kettle, etc.
I wouldn't be surprised if official 16A fused spurs start becoming more available. There appears to be a lot more in the way of 16A appliances coming out of Europe, where they are typically run on dedicated 16A radial circuits.
But Christian's a Continental at heart and *likes* radials, dammit ;-) Reducing the circuit MCB to 20A doesn't give him the 16A protection his drier manufacturer asserts is necessary, and to which he'd like to keep notwithstanding my perfectly-reasoned overload arguments ;-) To me it's looking more and more like mounting the 16A 6x32mm fuseholder (or the slightly pricier but easier-to-reset CBE) into a small box securely mounted to the back of the drier, having cut the existing appliance cable at a suitable point. This seems to meet the aesthetic requirements (keep existing switch, minumum wall projection) and the letter-of-the-manufacturer's-instructions ones with minimal expenditure (and no opening of the drier's cabinet, to avoid warranty issues).
Hmmm. Both the suggested fuseholder and the CBEs are very deep and couldn't be flush mounted in the space available. However, I have noticed item
360-7272, which should do the trick, though. Takes 10x38 fuses (where 16A is readily available) is rated for 30A (most fuseholders seem to have a 6.3A or
10A rating) and is base mounted, so can be stuffed inside a prepared flush mounting box.
However, are you allowed to have base mounted fuses that require the user (even though it is myself) to unscrew the box lid and have access to the live feed? (Presuming they aren't sufficiently clued up to throw the isolator).
Absolutely not. The circuit is absolutely intended for the purpose of running the dishwasher, tumble dryer and washing machine simultaneously. Although the ratings of the appliances might add up to more than 32A, it isn't by much if at all and thermostat duty cycle should sort it out. 20A would not cut it, however.
Hadn't thought of that. That way the excessive depth doesn't matter as you could mount sideways. Of course, the flex isn't protected by the fuse, then. However, I'm sure there is space for a surface mounted box on the skirting level, which would not be interfered with by the machine, which is integrated and so has a gap at the bottom. That way the flex can be cut right at the plug end and mounted into a junction box.
Super. And the flex *is* protected by the fuse, whereever it's physically located - an overload from the appliance will blow the fuse whether that fuse is physically close to the appliance housing, or back at the point where the flex leaves the pretty 20A switch. That's what "circuit" means, right? ;-) While short-circuit protection on the length of flex is provided by the 32A MCB back in the CU. This is the same principle which allows all the Euro-style equipment with on-board fuseholders (in some cases) or without (in the case of table lamps etc.) to be safely used in non-fused Schuko outlets, with flexes of only 0.75 or 1mmsq: the MCB provides short-circuit protection, while the equipment fuse (may be a built-in thermally-resettable one), or the Nature Of The Load (as in a table-lamp) provides overcurrent protection.
Glad we seem to have found a solution, anyway. Oh, as to your question about safe working on non-touch-proof fuseholders: given you have a DP switch ahead of the proposed fuseholder, in the same room as the fuseholder, I'm pretty sure you're in good shape (though I s'pose a warning label or marking on or inside the junction-box or sideways-mounted-box wouldn't hurt). And as a final aside... by the working of those twin evil-doers Sod and Murphy, the particular fuseholder you found in the RS range is sold in standard-multiples of 5 - so that's nigh on 20 quid, plus the VAT, if you're wedded to that particular model. Many of the other fuse-holders they sell, though, are sold in singles. Just one more thing we have to watch out for when selecting from the glorious cornucopia that is the RS product range for personal use, rather than work (where we incant "oh, the spares'll go into the Useful Items bin" ;-)
It begs the question where does this 10A and 16A bit come from? Presumably it is a Euro-market model which have either 10A 'kettle' type connectors or
16A Schuko (or whatever type it is.) Better to look at the power rating - which should (I think) be quoted by law. 16A would be around 4KW and I personally would be surprised if it really is as high as that.
Because it is stated in the handbook or on the unit it does not mean per se that it is fact!
According to the instructions, you can physically change the rating from 10A to 16A. I presumed that this was because European sockets are 16A, whilst the reduced rating allowed it to be sold in other markets where 16A connections are not available. The UK version is set to 10A with a 3 pin plug. The French model will have a euro plug and be set to 16A. You can replace the plug and change the setting, according to the manual. I suspect the setting enables or disables an additional heating element.
The manual gives drying times based on the selected rating. IIRC, one of the example loads goes from 120 minutes on 10A down to 85 minutes on 16A.
I suspect the low temperature programmes will be less affected by the change. Also, increasing the heater output might enable a greater air flow to be used, maintaining the same internal temperature, but removing more moisture, quickly.
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