Socket for fridge freezer

[mrbg07546]

i am sitting a new kicyeh and I was buying a few things for the sparky.

We will have a fused switched - for the 13a plug is it best I use a unswitched socket? What's typical

 

[EFLImpudence]

You do not need a fused switch; there is a fuse in the plug. Just a switch if you want one.

A switched or unswitched socket makes no difference.

 

[deadshort]

Hi, unswitched if its to be controlled from a switch above the worktop. If you are fitting a switch,or a fuse connection unit, i would advise they have a neon indicator.

HNY

DS

 

[EFLImpudence]

Why?

 

[DetlefSchmitz]

I used to buy neon fittings (MK) for certain locations but after a year they all stopped working. They got dimmer and dimmer and examination showed the inside of the glass had gone black. Never bothered since.

 

[JohnW2]

I used to buy neon fittings (MK) for certain locations but after a year they all stopped working. They got dimmer and dimmer and examination showed the inside of the glass had gone black. Never bothered since.

Indeed - I think that most of us must have experienced that.

Are they not (I can't say I've noticed it happening) shifting to LED indicators? Admittedly they would probably draw appreciable more current than neons - but at least most would probably last for at least a few years.

Kind Regards, John

 

[stillp]

would probably last for at least a few years

Or until an enthusiastic electrician meggered them!

 

[JohnW2]

Or until an enthusiastic electrician meggered them!

I wouldn't expect that to be a problem. I would imagine that (for cheapness) it would be done with just a resistor (and a reverse-polarity diode across the LED), in which case the current through the LED during IR testing at 500V would only be about double its normal operating current.

It would, of course, affect the IR measurement if left connected - but even neons may do that.

Kind Regards, John

 

[ericmark]

I have talked about the supply to fridge/freezer many times, both mine have little blue lights on all the time, however when the power has tripped I have missed seeing no little blue light. In the main I notice power has tripped when the emergency light comes on at top of stairs. We see a light come on much quicker than a light not on.

I have considered the wall mounted emergency light off same supply as freezer, a torch like this

will light with power failure and alert one to the fact it has failed. OK wrong plug on that one but you get the idea.

As to switched sockets I thought there is no need to ever turn off the power to the fridge or freezer, but I have been proved wrong, the one my dad had simply would not de-frost in the de-frost mode it continued to work, and moving out the unit to unplug is a pain, but a long stick and I can flick the switch, so yes a switch some where is a good idea. As to neon well all my units have a LED light on anyway so not required.

I have also considered a dedicated supply. Without a torch as shown however the problem is if it does trip will you find out in time? Unless wired in ali-tube without a RCD it could do the reverse to that intended, and result in you not realising it has tripped, not sure if amendment 3 has stopped you feeding a dedicated socket without a RCD?

 

[stillp]

For cheapness, I would imagine it would probably be done with an LED/resistor/diode combination that would not be happy to be supplied with double the normal running current.

 

[JohnW2]

For cheapness, I would imagine it would probably be done with an LED/resistor/diode combination that would not be happy to be supplied with double the normal running current.

Possibly.

However, I would think that it's very unlikely that either the LED or diode (only one of which would carry current, depending on the polarity of the {DC} IR test voltage) would be unhappy with double the normal current (which presumably would be very low, since one is not aiming for Blackpool Illuminations!). Nor, given the very brief duration of an IR test, would I think it very likely that the resistor would suffer as a result of 'double the normal current' (4 times the normal power dissipation). As for the diode (assuming it was reverse-biased by the IR test voltage), I'm not sure that exceeding it's PIV during the IR test would do it any harm - it would probably just behave (reversibly, without damage) as a high-voltage zener (with, again, a very low current, limited by the resistor).

So, whilst you might be right, I somewhat doubt that the LED/resistor/diode would, in practice, be at any appreciable risk.

Of course, the resistor would be plenty low enough in value to completely screw up the IR measurement, so the indicator circuit would need to be disconnected in some way (switching off the switch?) before testing. However, as I said before, the same problem exists with a neon. I've just tested an FCU with a neon and find that (with one polarity of testing voltage, but not with the other polarity), the indicated IR is 0.54MΩ at 250V, 0.33MΩ at 500V and 0.3MΩ at 1000V - so, again, necessitating disconnection (or 'switching off - e.g. by removal of an FCU fuse) of the indicator circuit before any meaningful IR test can be undertaken.

Kind Regards, John