Pat Test Question About Tumble Driers

[bertbuckie]

Hi all,

First off I do not believe I am wrong, however it has been known once before

My tumble drier is insured at home however the button broke and we called an engineer and when I unplugged it I found this ( see pics )

Now I PAT test as part of my job, and would like to hope I know what I am on about but the engineer told my wife (who I asked to argue as I could not be home) that the fault is the socket and all tumble driers do this to the plug after a year or so and also require a new socket!

Personally I have never seen this issue before unless an item is drawing too much current and I would instantly fail it.

Anyone got any input ?

 

[Marvo]

Classic signs of overheating. Possibly due to overloading, plug not pushed fully homer in the socket or corrosion on the plug pins/sleeves in the socket...causes resistance....causes arcing and heat....more resistance, more arcing and heat and so on until it fails. Replace both the plug and any socket(s) it's been plugged into, not just the plug. Check for wiring damage in the socket(s) also.

 

[Adam W]

It could be the socket. It could be that there is a high resistance connection in the socket rather than the tumble drier simply drawing too much current - if it needed more current than you can get safely and continuously from a 13A plug then why do the manufacturer supply the appliance with a 13A plug moulded to it?
I would expect evidence of overheating to be on the live pin, whereas this is on the neutral. I'd get the polarity of the socket checked as well.

Either way it sounds like you need to get someone to have a look at it.

 

[Pete999]

Looseconnection either in the plug top or the socket

 

[ruston]

Or a cheap tat socket in the first place, or maybe subject to years of heavy loads.

 

[telectrix]

socket from amazon or screwfix lap crap?

 

[hightower]

It's not a Hotpoint dryer is it? :smilielol5:

 

[ruston]

It's not a Hotpoint dryer is it? :smilielol5:

You are not allowed to plug products on this forum.

 

[hightower]

You are not allowed to plug products on this forum.

I know mate, but if anything it needs unplugging ​

 

[bertbuckie]

Socket changed and dismantled, looked fine when pulled to bits tbh, changed it first sorry forgot to mention that. Will run some other tests when I get home. Beko drier and didn't see anything about a recall on this model. Was also 100% plugged in its entire life as it's never moved and I plugged it in. I'm in agreement about the neutral tho, very strange.

 

[ruston]

Are you spurring me on?

 

[hightower]

Are you spurring me on?

Aye, you need putting in to isolation​, much like that dryer.

 

[bertbuckie]

He fitted a nice second hand plug for us tho! With a previous pat sticker still attached lol.

 

[hightower]

He fitted a nice second hand plug for us tho! With a previous pat sticker still attached lol.

I've just found a box of IEC leads (kettle leads) at work, brand new as in 2 years old but never used. Each one has the cable tie on still, and the little plastic prong cap over the plug end. And each one has a PAT sticker on. So these 100 or so IEC leads have each been uncable tied, unprong capped, tested, labelled, prong capped back up, and cable tied back up..... or the tester has thought "here's an easy £50" as he blindly stuck a sticker to each.

 

[Adam W]

I've just found a box of IEC leads (kettle leads) at work, brand new as in 2 years old but never used. Each one has the cable tie on still, and the little plastic prong cap over the plug end. And each one has a PAT sticker on. So these 100 or so IEC leads have each been uncable tied, unprong capped, tested, labelled, prong capped back up, and cable tied back up..... or the tester has thought "here's an easy £50" as he blindly stuck a sticker to each.

You CYNIC! :smilielol5:

 

[bertbuckie]

Lol class!

 

[Pete999]

You are not allowed to plug products on this forum.

someone had already plugged it in

 

[bertbuckie]

SO! Did the normal tests, continuity, fine. insulation, fine. Sub leakage.... ( and I would never do this unless I suspected something ) 4.19mA - this still doesnt explain the issue but iirc its meant to be under 3.5mA for stationary equipment?

 

[bertbuckie]

..... mind you it could be classed as a heating appliance up to 5mA I guess.

 

[bertbuckie]

2.7kw tho so should surely be 0.75mA per kw meaning just over 2mA

 

[Pete999]

SO! Did the normal tests, continuity, fine. insulation, fine. Sub leakage.... ( and I would never do this unless I suspected something ) 4.19mA - this still doesnt explain the issue but iirc its meant to be under 3.5mA for stationary equipment?

Are you sure it should be classed as stationary equipment? it's plugged in not hard wired, tried looking back at my notes but it's to wet to go to the shed, your the expert.

 

[bertbuckie]

Not 100% no lol..... but 3.5mA is the max iirc for anything unless it uses an industrial plug.
Again, please please correct me if I'm wrong, i'd rather know.

 

[Adam W]

I can't help thinking you're barking up the wrong tree with all this talk of PAT testing (or rather II&TEE). Measuring the current consumption of the appliance when it's working flat out may tell you something, but I think cogitating over the permissible amounts of leakage current is somewhat fanciful.

It's fair to say the damage to the plug was caused by overheating, which could be caused by overcurrent or a high resistance joint.

I've seen this before, but it was with a commercial washing machine in a hotel laundry being plugged into a 13A socket. The fuse would blow every now and again, but the people who worked in the laundry seemed to have accepted a fuse as a consumable, like a light bulb, which needs changing every now and again. Both sides of the double socket (metal clad) displayed signs of overheating, and they'd run the flex across the floor under a mat so they could use another 13A socket. After checking the power consumption, flex size etc I changed the plug and socket for 16A with a breaker in a separate enclosure and it seems to have been fine since.
This was a commercial washing machine though - I wouldn't expect to have to do this with a domestic appliance, least of all one which comes fitted with a moulded 13A plug.

If there were an overcurrent the fuse would have blown (which you haven't mentioned), which leaves a high resistance joint.
Most electricians will have gone to test a ring final and come across a socket with an abnormally high resistance, plugged the socket adaptor in a few times then found it gives a sensible result. This is because the friction from moving the adaptor has worn away any oxidation on the contacts and it now makes better contact.
Did I read that you plugged the drier in when you bought it and it's been like that ever since? It could be that in an environment where they may be hot, damp air coming out of the drier a layer of corrosion has built up between the socket and plug pin, causing a high resistance joint; in the absence of any further investigation I'd be prepared to put it down to this.

 

[bertbuckie]

Quite possible Adam, thats why I said earlier I couldn't understand the high leakage making any difference.
It is also a condenser drier and not much damp around it tbh, in a well ventilated room but it is possible I guess, strange one to me tho tbh.
It has never popped a fuse.

Just trying it in a different socket under observation so I shall report in 45 mins Bet it gets roasting hot lol

 

[Marvo]

.....I'm in agreement about the neutral tho, very strange.

I don't see why it should be more likely or prone to overheating on the Neutral side.........:thinking:

 

[bertbuckie]

I don't see why it should be more likely or prone to overheating on the Neutral side.........:thinking:

That's what I meant. Running ATM as I had to pop out earlier so will see if it gets hot.

 

[bertbuckie]

Plugs warm, not hot. Cables hot tho.

 

[ohreally]

I find plugtops exhibiting thermal damage tends to be on the neutral pin.

New plug/ flex and monitor the situation.

 

[ackbarthestar]

You CYNIC! :smilielol5:

Try this for a test ........ https://www.youtube.com/watch?v=CfB0Vcft7uA

I suspect the problem is a loose neutral in the socket - Does the socket get warm?

 

[bertbuckie]

So! Thread resurrected, 3 months later and we have THIS!
And to top it off I find this....
https://www.aspokesmansaid.com/shop...ire-after-tumble-dryer-plug-burns-into-socket

Called them, they want to send the same engineer, which I have refused tbh as I find him incompetent. I offered to return the dryer to the shop, but they say this is no use. Where do I stand?

 

[bertbuckie]

And to top it all off, I have young kids, live is VERY exposed ( my 7 year old actually pointed the hole out to me, good lad! )

 

[Risteard]

The first set of pictures shows it on the neutral, but the second set of pictures shows it on the phase.

 

[bertbuckie]

Aye I know, strange eh

 

[bertbuckie]

Possibly just the weak point on either?

 

[Richard Burns]

If you did not change the socket last time then it is very likely this would have happened as the internal socket connections would be corroded already from the previous heat.
In this case however it look like there is a poor connection at the fuse, presumably a slightly dirty fuse or possibly heat transferred along the brass from a poor line connection.

I would change socket and plug and also the cable (as that got hot last time) possibly using a higher csa cable to better handle the current.
However the key part is to have good connections in the socket and plug both in the wiring and on the internal connections of plug to socket.

 

[telectrix]

cheap tat plug and socket IMO.

 

[bertbuckie]

Different socket, I changed it last time

 

[Flanders]

If the tumble dryer was pulling to much load it would blow the fuse i would say it down to poor contact with the fuse in the plug i also noticed that you left tbe card board wiring diagram on the plug the on,y otheridea i can think is that the tuble dryer in running at about 15 amps and the fuse is just hanging on in there , i would recommend doing a load test to see how many amps the tumble dryer is pulling and if its more than 13amp you have a good argument to give to tne suppliers

 

[bertbuckie]

Hi Flanders, the engineer who did the plug from knowhow left the cardboard on lol, I shall try and get an amp meter as I would imagine its towards the end of the cycle it draws the most current tbh.
Someone also said cheap socket and plug... twice ?

 

[Flanders]

Hi Flanders, the engineer who did the plug from knowhow left the cardboard on lol, I shall try and get an amp meter as I would imagine its towards the end of the cycle it draws the most current tbh.
Someone also said cheap socket and plug... twice ?

From my experience every time of have found heat damage like this it been due to loose or poor ccnnection at terminal points , asit was on the neutral on the molded plug and then on the live on the replacement plug , i would say that the molded plug had a bad connection neutral (may of been a comon fault at the manufacturer ,and )the new plug had a bad connection either at the connection or on the fuse holder. If you can take thecover of the plug you may see exactly were the point is , somtimes on cheaper plugs the fuse holder clips never seam very good just my opinion.

 

[Deleted member 72666]

Hi Flanders, the engineer who did the plug from knowhow left the cardboard on lol, I shall try and get an amp meter as I would imagine its towards the end of the cycle it draws the most current tbh.
Someone also said cheap socket and plug... twice ?

What's your reasoning behind that statement?
From past experience anything around 2kW and above requires a decent plug (MK Tough plugs fit the bill) and socket, none of the cheap stuff that's available, failing that a decent fcu.

 

[bertbuckie]

Reasoning is as the machine uses the heaters as opposed to the spin only. Spoke directly to the company director at know how and we are getting a new dryer, similar faults have been found on others it seems.

 

[Deleted member 72666]

Reasoning is as the machine uses the heaters as opposed to the spin only. Spoke directly to the company director at know how and we are getting a new dryer, similar faults have been found on others it seems.

'Spin only' on a tumbler drier? What purpose does that serve or is this a washer drier?

 

[bertbuckie]

No, but it has various stages of cycles, including anti crease etc. What I meant was at the very start it might not be pulling as much as later on that was all.