SWA to T&E

[DIYTom]

Such things might be available, but that freezer is not one of them.

Minimum Ambient Operating Temperature 10°C

The information seems a bit confused on that. It also says:

This chest freezer is also suitable for use in a dry garage.

So unless they think that garages never get below 10 I would guess there has been a mistake somewhere. Ours certainly operates fine and stays nice and cold all year long.

 

[deadshort]

Hi John, Thanks for the response. Yes the 2.5 is supplying the single socket, I know it's 2.5 as I opened it to have a look. As for whether it's acceptable I would submit to your better judgement?

Having 2.5mm cable supplying one socket is not, per se, a problem - the potential issue is having it protected by a 32A MCB. Provided the cable is not too long, I would probably be happy - but others may disagree!

...The problem I have is that there is very little space available in the conduit space (running through dining room, kitchen and bath room) to easily run cable out to the external wall (diameter wise) so swa may be too thick to do so. ... I am wondering if I (or my electrician) can run twin and earth to a more convenient junction inside the house, then from that junction to the shed in swa?

There is no reason why the indoor bits have to be SWA - so, if it would help,it would be perfectly acceptable to have the initial (indoor) part of the run in 6mm² (or maybe 4mm²) T&E, before changing to SWA at some box (or accessory) - as I said, maybe making the join at the present socket. As I said, I'm sure your electrician will have views on what approach should be taken.


Kind Regards, John

Odd, 1.5mm flex is ok on a 32a mcb but 2.5mm T+E is'nt ?



DS

 

[EFLImpudence]

Because it was going to supply the shed.

 

[deadshort]

and…………….

DS

 

[JohnW2]

Odd, 1.5mm flex is ok on a 32a mcb but 2.5mm T+E is'nt ?

In this context (with a single socket on the end of it, hence a 13A fuse), there is no difference between 1.5mm² and 2.5mm². Per the actual word of the regs, either is OK in that situation (provided fault protection is OK), since 433.2.2 allows downstream over-current protection if either 433.2.2(i) or 433.2.2(ii) are satisfied. However, it seems that some folk around here are not comfortable unless the latter is satisfied, even if the former (adequate fault protection) is already satisfied - and therefore are not happy with downstream protection if the length of cable in question is greater than 3m. Hence my comment about length.

Kind Regards, John

 

[JohnW2]

Because it was going to supply the shed.

I presume that DS's comment related to mine about the existing situation of a single socket (and nothing else) supplied by 2.5mm² cable protected by a 32A MCB.

Kind Regards, John

 

[EFLImpudence]

Sorry, I misunderstood the point.

 

[deadshort]

I was not aware that length was an issue in this context, sadly in life it usually is.

I enjoy the pick and mix regulation application formula

Kindest regards,

DS

 

[ericmark]

Number of points.
1) Running a single socket with 2.5mm cable on a 32A MCB has a maximum length of 3 meters. So swapping to 6mm or more would be good.

2) A frost free fridge/freezer must be able to run the water to the evaporation tray on the motor, many fridge freezers also have no separate control fridge to freezer and they only cool the fridge there is no heater so ambient must be above fridge setting and clearly not below freezing point. The SN climate class is +10°C to +32°C the rest start at +16°C so likely all freezers will be either +10°C or +16°C some chest freezers (i.e. no frost free) may be able to used well below the 10°C but likely will still say 10°C as they are SN climate class.

3) Using an earth rod instead of the house earth may be possible but there are many factors to take into consideration and it's not something for the DIY guy to work out.

4) Fridges and freezers in the main have single phase motors and volt drop is very important. Mine have three phase motors and inverter drives but that is unusual. This is why most fridges and freezers state on instructions not to power from an extension lead.

5) Don't be fooled by Class A, A+ or A++ these are based on the standard annual energy consumption (SAEc) and this is different for chest, upright, frost free and all the climate classes so size / energy used may give a chest an A rating but with a frost free upright freezer the same size / energy used T class climate could be A++. So 198 kWh with a 288 litre chest is A but upright frost free built in class T at 194 kWh is A++ so rather pointless to compare items using the rating.

 

[ericmark]

I was not aware that length was an issue in this context, sadly in life it usually is.

I enjoy the pick and mix regulation application formula

Kindest regards,

DS

433.2.2 The device protecting a conductor against overload may be installed along the run of that conductor if the part of the run between the point where a change occurs (in cross-sectional area, method of installation, type of cable or conductor. or in environmental conditions) and the position of the protective device has neither branch circuits nor outlets for connection of current-using equipment and fulfils at least one of the following conditions:
(i) It is protected against fault current in accordance with the requirements stated in Section 434
(ii) Its length does not exceed 3 m, it is installed in such a manner as to reduce the risk of fault to a minimum, and it is installed in such a manner as to reduce to a minimum the risk of fire or danger to persons (see also Regulation 434.2.1).

 

[ban-all-sheds]

The information seems a bit confused

No - it is not the information which is confused.

So unless they think that garages never get below 10 I would guess there has been a mistake somewhere.

What they think about garages is irrelevant. I live in London, winter hasn't really started yet, but I'd bet what's left of my pension that it will get down to less than 10° in both my shed and my unheated detached garage tonight. Both of which are dry.

Ours certainly operates fine and stays nice and cold all year long.

Check on the label that it specifically says that and you'll be fine.

And that JL one does not say that it will be unconditionally alright in an unheated outbuilding. It says "Minimum Ambient Operating Temperature 10°C".

I'm sure that there is much conservatism there, much playing it safe, and that it will work fine at temperatures less than that, and with temporary excursions to quite a lot less than that. Just as I'm sure that there is much conservatism in some use by dates on food, and that I can trust my nose and eyes to know if I can eat something "too old".

But I'm equally sure that if I get it wrong it's entirely my fault, and just like I would not set out to design a shopping schedule which relied on eating food which was past its use by date, I would not set out to install a freezer in an environment which the makers said was unsuitable, and nor would I advise people to buy food which they knew would be past its use by date before they used it, nor advise them to install a freezer in an environment which the makers said was unsuitable.

Dry or not, if it gets below 10° then you've got no comeback against JL if it doesn't work properly.

 

[JohnW2]

Number of points.
1) Running a single socket with 2.5mm cable on a 32A MCB has a maximum length of 3 meters. So swapping to 6mm or more would be good.

As I said, that's what some people here seem to believe. However, if you actually read 433.2.2 (which you correctly quoted in your next post!!!) is says that 2.5mm protected by a downstream OPD (in this case a 13A fuse) is OK if EITHER the cable has adequate fault protection AND/OR is no more than 3 metres in length (from CSA reduction to OPD). Hence, as I said, if there is adequate fault protection (which will virtually always be the case) then there is not a 3 metre maximum length.

Kind Regards, John

 

[JohnW2]

I was not aware that length was an issue in this context, sadly in life it usually is. ... I enjoy the pick and mix regulation application formula

You don't need to take my word for it that "some folk here" misinterpret 433.2.2 such as to believe that "length is an issue in this context" - in the very post after this one of yours, eric is asserting that there is a 3m maximum for downstream overcurrent protection. !!

Kind Regards, John

 

[EFLImpudence]

Number of points.1) Running a single socket with 2.5mm cable on a 32A MCB has a maximum length of 3 meters. So swapping to 6mm or more would be good.

As I said, that's what some people here seem to believe. However, if you actually read 433.2.2 (which you correctly quoted in your next post!!!) is says that 2.5mm protected by a downstream OPD (in this case a 13A fuse) is OK if EITHER the cable has adequate fault protection AND/OR is no more than 3 metres in length (from CSA reduction to OPD).

Whilst that is true it is not the whole story.

The EITHER choice is: three metres OR be in accordance with 434.

However, one of the conditions in 434 is also the three metre length restriction.
Unless I am reading it wrongly, I can see no way round the restriction.
It also states that there shall be no socket outlets.
I am uncertain of the reason for a three metre rule.


Apart from that, could the length be increased by using omission of overload as the cable cannot be overloaded because of the plug fuse(s)?

 

[JohnW2]

Number of points.1) Running a single socket with 2.5mm cable on a 32A MCB has a maximum length of 3 meters. So swapping to 6mm or more would be good.

As I said, that's what some people here seem to believe. However, if you actually read 433.2.2 (which you correctly quoted in your next post!!!) is says that 2.5mm protected by a downstream OPD (in this case a 13A fuse) is OK if EITHER the cable has adequate fault protection AND/OR is no more than 3 metres in length (from CSA reduction to OPD).

Whilst that is true it is not the whole story. ... The EITHER choice is: three metres OR be in accordance with 434. ... However, one of the conditions in 434 is also the three metre length restriction. Unless I am reading it wrongly, I can see no way round the restriction.

We've been through this before, and the regs seem pretty confusing. Whilst what you say is essentially true, both 434.2 (which requires, normally. upstream fault protection) and 434.2.1 (which introduces the 3m and 'mechanical protection' requirements) are qualified by "unless 433.2.2 applies" - which leaves me wondering what on earth is being said!

It also states that there shall be no socket outlets.

I presume that means 'along the length of the (down-stream-protected) cable', not at the end - it actually talks of 'connections for current using equipment' - if such was not allowed at the end, there would be no point in having the cable!

I am uncertain of the reason for a three metre rule.

I presume it's just an arbitrary number, which was consdiered to be 'a reasonable compromise'. The cable obviously gets no protection from the downstream OPD in relation to faults in the cable itself - and I suppose that the longer the cable,the more likely they are to arise.

Apart from that, could the length be increased by using omission of overload as the cable cannot be overloaded because of the plug fuse(s)?

If you're talking about 433.3.1(ii), that also invokes the requirement for "fault protection per 434'.

Kind Regards, John