Fused Spur education

[eveares]

Why would a gas hob need an FCU?

I suppose he is thinking about the ease of turning the electrics (i.e. ignition) off for the gas hob.

 

[ericmark]

To have a FCU where one has a plug is clearly not required. However I can see why with some items you would want to remove the chance that some one has unplugged it, the boiler is a good example. Also a fuse produces heat so a plug needs to be in free air to cool. So an oven without a cooling fan may need a FCU so heat from fuse goes into wall as not enough free air. However following the 2kW recommendation larger items should have a dedicated supply anyway.

There was a rule on motors over a set size having local isolators, However integral motors like with a fridge/freezer are exempt from this rule. Also years ago we would always have an isolator for a washing machine because of damage caused if weights came lose. But today the washers auto stop with unbalanced loads so no longer required.

Switches to hidden sockets are handy. A fridge/freezer I have found although it has a off position they don't always go off. Pulling it out to de-frost in not fun much easier with simple switch. I think to use a switched FCU has some advantages. You know the switch is big enough even if you swap a single socket for a double, and by removing fuse you can lock it off. It is not so much have a fuse but having means to lock off.

However double fuses means a lower prospective fault current which could be a problem with some refrigeration units which is why it stated on so many instructions not to use extension leads with them.

So it comes down to personal preference rather than a fixed yes or no. If you can group all your isolation switches together with a grid switch with names for each switch like washer, fridge etc then no real point in using a fuse as well. But if the option is 20A switch or FCU then they take same space so really does not matter which.

With modern inverter washers, freezers, and fridges the resistance of a second fuse is not a problem. Even with older units most houses are not on the limit for volt drop and in real terms two fuses again not a problem. So theroy says don't double fuse, but in practice it does not matter.

For portable appliances they have to be designed for Europe so if they need a fuse it will be built into the appliance as in rest of Europe there is no fuse in the plug. The fuse in plug is only to protect the cable. However it is not the same for fixed appliances when fixed the manufacturer can stipulate which external protection is required. So boiler may well need a FCU, however I would expect most manufacturers to put fuses in the boiler and not rely on one in FCU.

 

[kai]

There is one situation that a FCU will be needed, if the Earth Loop Impedance dictates it - The ZS can go as high as 2.5.ohms for a standard 13amp FCU, so is handy for making that Immersion Circuit comply, when it is fed by a C50 format 20amp breaker etc.

 

[ban-all-sheds]

Why would a gas hob need an FCU?

I suppose he is thinking about the ease of turning the electrics (i.e. ignition) off for the gas hob.

That may be a perfectly good reason to want one.

 

[bernardgreen]

That may be a perfectly good reason to want one.

Definately. A neighour accidently spilt a saucepan of water on a gas hob control panel, water got under the knob(s) and shorted the ignition switch(s). Ignition firing continuously and only way to stop it was to turn off kitchen sockets. Panic call to me. A bit of searching discovered a socket behind a drawer unit into which the hob was plugged.

 

[dpm_dpmartin]

In the end I purchased 3 Fused Spurs instead of my original thinking of 6.

Helped to reduce the overall cost of my order by a few Quid, so I'm happy with that. Still over £200 on sockets and switches, but I'm hoping they'll look the business.

P.S. - I pointed out, via an email, to The Electrical Counter, that it was cheaper to buy 2 x 5 pack of double sockets than it was to buy 1 x 10 pack and they kindly reduced the price of the 10 pack, this was reflected immediately on their website.

 

[ban-all-sheds]

Panic call to me. A bit of searching discovered a socket behind a drawer unit into which the hob was plugged.

It was remarkably foolish, stupid even, of the householder not to have looked for the means of connection/isolation of the hob when they moved in.

Ditto all other appliances, ditto verifying/adding circuit IDs to the CU, ditto external and internal stopcocks, ditto checking that they work, ditto any inline valves for basins, showers, toilet cisterns....

 

[bernardgreen]

It was remarkably foolish, stupid even, of the householder not to have looked for the means of connection/isolation of the hob when they moved in.

You do not know that they didn't look. In fact when I found the socket she recalled having been told it was there. That was about ten years ago when she moved in. When things are going wrong not every one can remain calm cool and able to collect their thoughts and memories.