Hi all.
Could I please have your guidance and opinions on the use of extension cables as a permanent fixture?

We currently have three sewing machines that are powered through an extension, via a 4 gang trailing socket. There are no trip hazards or hanging cables and everything has been PAT tested. The extension has an RCD breaker at the mains. The distance that the cable is extended is about 30ft.

The reason for using the extension is financial, the machines will not be moved from this location, and people further up the food chain than I have decided that it’s cheaper to use a cable than to have conduit and sockets put in.

Thanks
Andy

I would always suggest use as a temporary measure, dependent on the culture this can often lead to overload and increased fire risk. You haven't told us the current rating for the 3 machines.
I too work for a large LA who would NOT be happy with this.
I would suggest that by definition, extensions cannot be described as a "permanent fixture".

It is a culture thing that I am concerned about. There seems to be an increase in the use of extensions, there are no controls as to who uses them, when and where. The management here are "reluctant" to take any H&S responsibility at all. I am trying to get some control measures in place. I must admit that I am a little shocked at the lack of commitment as the last warehouse burned to the ground.

You ask can they be used on a permanent basis, the answer is quite plain NO. You need to look at an alternate way of providing power to each workstation. Can you rearrange your workplace to get better supply? Can you reduce the number of workstations by using them more effectivly? You really need to find a more permanent solution than simply allow extension leads to be used permanently, as they do create the risk of serious injury.

First of all PA testing is historical and only states that the cable was ok up until it was tested, that's why PA testing is not worth anything. Extention cables are well know to be subject of many abuses. They can create tripping hazards as well as other safety risks. The long term use of extentiion leads is not only undesirable but bad practice and even Lord Young would not condone using them above a safer method.

I know one person who tripped on a similar arrangement and received several tens of thousands of pounds, as compensation for a shattered wrist.
While looking at the current consumption at each machine may give the impression that the combined load is within the maximum ratings of the [230volt] extension, the start load will be in excess of the maximum load of the extension.
The 4-in-1 type of 230V extension are really NOT to be trusted at any load near their limit. Heating DUE TO POOR PLUG-TO-SOCKET contact is their main failure state.
The wall-socket to machine length of cable is prone to wear, and hence exposure of the live rail to human contact.
At the very least the socket-to-remote socket cable should armaflex or similar.
The whole arrangement is an accident waiting to happen.

I would not be happy with an extension being used as the permanent supply to 3 discrete separated pieces of equipment.
In other scenarios where they are used in a semi permanent nature to supply for example a pc workstation at one location then their use is a “little” more tolerable.

HOWEVER, if they are a permanent fixture then they must become part of the fixed installation, as you are now defining them as part of the fixed installation.
Thus to meet EAWR89, then really they must comply with BS7671:2008 as this is recognised by HSE as the "main" method of compliance.
IF the extensions do not comply with BS7671 and are a permanent fixture thus part of the fixed electrical installation then they probably do not comply with EAWR89 in the eyes of HSE.
How much would it cost to get a competent electrical contractor in to provide 3 additional socket outlets wired in say plastic conduit, plastic trunking or perhaps SY (lightweight steel over braided cable)?
A lot less than an accident or a prosecution I'll vouch.
If the installation of the extension lead does meet the requirements of BS7671 then they would be acceptable perhaps pending compliance with other requirements.

A few hopefully constructive comments on the previous responses.

I’m not getting into housekeeping!

The maximum load of these devices is limited by the 13A fuse in the connecting plug top. However, these fuses will not protect against small overloads of a long duration. I have just investigated a failure in a fixed install of a 13A fused connection unit which had melted and nearly caught fire due to a small overload of long duration, the circuit drew 19A max on an intermittent basis, instead of a max of 13A.
The failure took weeks to manifest itself.

These leads are manufactured to a price thus quality is often barely acceptable.

An “annual” (etc.) PAT test as is commonly accepted, does not meet the full requirements of the IET CoP for “PAT”.

The RCD would not necessarily trip prior to a fire, an RCD only protects against “live to earth” faults. It does not protect against “live to neutral” faults.
An RCD socket in this scenario would only protect the user and machine etc. against faults downstream from that device. An upstream RCD will protect the user, the equipment and the extension etc.

The earth fault loop impedance required to trip a 30mA RCD is 7666 Ohms.
A 30mA current for 10ms (0.5 of a 50Hz cycle) is pretty survivable based on the IEC research, this is why we utilise 30mA devices for additional protection. They must not be relied upon for basic protection.

RCD devices must be tested every 3 months for compliance with “PAT”, BS7671 & manufacturers instructions.

Start loads may be in excess of the limit it may not, however remember motor loads may draw up to 50 times their rated current on start for a very short time depending on design).

Cascaded 30mA RCD devices do not offer discrimination in the event of a fault, unless the upstream device has a time delay, however, realistically this can only be done once.
However, when cascaded they do offer redundant protection.
Lack of discrimination in the event of a fault is in contradiction with BS7671, however, the designing engineer can mitigate this with competent checks and suitable documentation. It may be preferable in certain circumstances.
I often do this cascading in medical installations by design to offer redundant protection even though it is not in compliance with certain regs in BS7671, in my opinion the possible additional benefit outweighs these regs.

HTH in some small way?

ron,

Quite, in this scenario, there is a possibility of what is known in BS7671 as "high protective conductor currents", which would require the application of "high integrity earthing" to comply with BS7671. Hence probably EAWR89.

As these leads from the OP appear to be part of the fixed electrical installation then they would need to comply with these requirements, which they cannot, by their design.

Good point, missed that one, as to me sowing machines are still like my Mother's old Singer!

I would however with hindsight expect modern commercial / industrial machines to have variable speed drives and other computerised systems which may well bring them into line with these requirements!

Good shout my man!

I disagree with Bob on this; PA testing will weed out what is defective and has, so far, not harmed anyone. To go to the OP I believe that extension leads are inevtiable and acceptable in some circumstances for example under a desk running the PC, monitor and phone charger - so long as they are PA tested. However, for machinery (and we don't know the rating of said sewing machines) a permanent installation would be desirable.

quote=john_80]
One thing though, if the extension leads aren't causing a trip hazard, how are they routed to the workstation?

I wouldn't be so sure. I audited a site last year and found daisy-chained multi-ganged extensions with double-plug adaptors. All with shiney new PAT labels on dated the week previous! I do have a photo if anyone is interested but you'll have to give me some time to airbrush out the FM Providers name.

I suppose if you test anything as an individual item it will pass, but when you connect everything together will it still pass?

Paul, it must be getting through as I understand most of your posting, well said and I agree. Also in agreement with everybody who says it is not advisable.

Sorry to drag this up again, however, I thought it quite relevant!

My NICEIC Winter 2010/2011 magazine turned up this morning (I am also an NICEIC Approved Contractor).
As I was sat down having a cuppa I had a quick look through.
The ESC quarterly magazine is bundled with this.
I picked that first and on pg. 6 is a letter discussing extension leads!
This referred to an article in the Autumn edition, which I had not even opened, was too busy.
So I dug this out.
It makes interesting reading.
I have attached a link I hope and typed in the web address as I’m not good with these things, to the on line version of the article.
There are 3 there, I have not read all of them yet myself!

http://www.esc.org.uk/bu...tension-cord-survey.html

If the link does not work go to “esc.org.uk” and select the “business and community” bit from the top menu bar thing on the rhs and then inn the side bar on the left under research click “extension cord sets” which will take you to links to the 3 docs.
The link above if it works will take you straight there.

Hope this helps.

(Chris, I’m messing around in the office this a.m. so I’ll dig up that PAT info you wanted and email it over later.)

Loose cables in construction are short term use and it would be impractical to have permanent fixes for temporary cables.

Risk assessment comes in here as there is a smaller requirement for cables on construction sites due to the availability of rechargeable hand held tools.

Don't compare construction sites with permanent premises.

I have lost count of the number of times that PAT has been discussed and I do agree with Bob that in some cases it is overused, over relied on and 'sold' as the panacea of electrical appliance safety; which it isn't.

But I suggest that it does have a part to play in an overall maintenance regime. PAT may identify faults that aren’t apparent in a formal visual inspection, and similarly, a formal visual inspection may well reveal faults or problems that a PAT doesn't detect.

Just a thought

I often hear the MOT argument. I for one take a little comfort from knowing that vehicles have an MOT, that lifting equipment has a TE, etc etc etc. As I have said, PAT is not the panacea, but I do think that it has it's part to play in an overall maintenance regime, alongside formal inspections and perhaps most important pre use or user checks. I wouldn't rule it out as having no worth!

Sad as it is, as I sat in the Drs waiting room this morning, it struck me that the PAT/MOT waste of time/only historical argument/analogy might need some further examination. Of course, much the same argument could be applied to the formal visual inspection.

So if PAT is a waste of time (using the MOT analogy) and by the same token, formal visual inspections are similarly a waste of time (as they only record the condition at the time of the inspection as well) I am left wondering where that leaves us or indeed leads us? Relying on pre use/user checks only? Now hands up those that would be comfortable relying on that, either as a robust, practical and pragmatic management strategy or as a defence in court?

As I have already said, PAT is not the panacea of electrical kit maintenance, but I suggest that it does have a part to play in the overall management of electrical kit, in line with HSE/industry guidance. There are faults that could be identified with PAT that wouldn't be obvious in a formal visual and vice versa.

Sorry I know we have strayed from the original query. Righ off to grab my stab vest and helmet :-)

Paul, indeed, and I had just read your post on the microwave thread, and I think that you have hit the nail on the head when you say

"On their own, I also feel each is a waste of time, however, correctly combined, I feel that an employer would have a robust defence and would have acted far and beyond what is required".

It just struck me rather late in the day that the MOT analogy works equally 'well' for both testing AND inspection/examination, and that it left us with a bit of a problem! If we used the MOT argument not to test then applying the same 'logic' we would use the same argument not to inspect/examine and we would be left with a maintenance regime consisting of ................... well not a lot.

One of these days we WILL crack the old PA test issue :-)

Kind regards