Live wire scorched in plug

nkay1985

Hi guys. Hoping some of you can help me out. My wife said the tumble drier stopped and had no lights on so I took a look. Determined it was either something at the plug or the drier itself. Opened up the plug and found what you can see in the attached photos.

So somehow the live wire in the plug has burned and basically disintegrated. Can anybody shed any light on why this might have happened and the best thing to do now? Like is it ok to just cut it back and re-wire it? It hardly is?

Appreciate any help or advice.

Thanks.

KK4SAM

Replace the plug as there is heat damage to the fuse holder.

meercat

Yeah cut the cable and reconnect to new plug
It may be prudent to replace the socket too

KERSPLAT!

Looks like the live became loose causing arcing and deterioration of the insulation. As above, the the cable and connect to a new plug top ensuring connection are tight.

dev100

nkay1985 wrote:

Appreciate any help or advice.

Usual culprit is loose wires

dev100

Usual culprit is loose wires.

It could be a cheap plug and nasty plug or that the live wire wasn't tight in plug it's generally always loose wires that do damage

Replace plug and keep an eye on it . Never leave a tumble dryer unattended

nkay1985

Thanks guys. I'll cut it back and wire it with a new plug. Hopefully it'll be grand after that.

Melodeon

Looks like the original flex on the drier has been extended or replaced with stranded white PVC cable intended for running through conduit or trunking.
It's not helping the poor connection issue in the plug due to its stiffness and relative inflexibility.
Replacing that with proper flex would improve things a good bit.

byte

Was the clamp just on top of the 3 cables, or on the sheath aswell? Looking at the pics, it seems like the 3 cables were under the clamp with the dents on them.

Also noted that the clamp screw was rusty, was there steam in the room or moisture that might've contributed to arcing inside the plug?

byte

Was the clamp just on top of the 3 cables, or on the sheath aswell? Looking at the pics, it seems like the 3 cables were under the clamp with the dents on them.

Also noted that the clamp screw was rusty, was there steam in the room or moisture that might've contributed to arcing inside the plug?

nkay1985

I think the clamp was just on the three wires and not on the sheath.

The original flex would have been removed alright. The dryer is in a downstairs bathroom (essentially used as a utility room) so obviously can't be plugged in there. The power cable is run through a hole in a stud wall and it's plugged in in the hallway when in use.

As such, there shouldn't be moisture anywhere near the plug but I saw that rust myself so obviously there must have been. It's a vented dryer and the vent hose has on occasion fallen down from the window and onto the floor of the bathroom so I guess it's possible that some moisture got through the hole and at the plug.

Somebody said replacing it with proper flex would make a better job. How would I go about doing this?

Stoner

nkay1985 wrote:

Somebody said replacing it with proper flex would make a better job. How would I go about doing this?

Do you mean replacing the ducting with flexible ducting?
The extension lead option into a bathroom is a bad idea anyway for a start particularly if any of the cable on the extension lead is still left coiled up. Possibly your other advice related to having a lead that's not on a coil and is the correct length with little or no slack they may have suggested getting a prefabricated lead at the correct length with good quality accessories like duraplug.
I know you are saying that this is effectively a utility room but I'd say it's likely that it's used for both sometimes.
All we can tell you is that it's against the wiring regulations and dangerous to have an extension lead , never mind a dryer in there

Regarding the flexible ducting. This is available in plumbing shop. And it's best to have the ducting from the dryer to the exterior as short and straight as possible. A hole through the wall at the same height as the exit vent on the dryer and a very short run of ducting is best.

If you end up changing the room to a utility room

Have you considered changing the dryer lately ? Maybe to a heat exchange unit , self cleaning etc far more efficient. Samsung, Siemens and Bosch make decent ones. Get the drainage kit and let it drain away itself.

nkay1985

Thanks for the post, not sure I explained the layout correctly. The dryer is in the bathroom. Its power cable is running through a stud wall and plugged into a socket in the adjoining hall.

In order to facilitate this, the original plug was removed from the dryer, the cable run through the stud wall and the plug re-attached but obviously the flex etc on a factory plug that it had originally would be better than the way it ended up being wired as a result of the above.

I'm really just wondering the best way to re-wire the plug at this point.

Not going to be in a position to change the dryer anytime in the near future. Think it's ok anyway.

dev100

nkay1985 wrote:

Thanks for the post, not sure I explained the layout correctly. The dryer is in the bathroom. Its power cable is running through a stud wall and plugged into a socket in the adjoining hall.In order to facilitate this, the original plug was removed from the dryer, the cable run through the stud wall and the plug re-attached but obviously the flex etc on a factory plug that it had originally would be better than the way it ended up being wired as a result of the above.I'm really just wondering the best way to re-wire the plug at this point.

Electrical items in the bathroom . I wouldn't be fond of that !!! Anyways you say the factory plug was removed ? Just the plug or the cable was removed back at the dryer and a new cable was put in ?

KERSPLAT!

It's likely the moulded plug top was cut off and another put on. Just wire it to a new plug top ensuring tight connections, it'll be fine.

I wouldn't be a fan of having it in the bathroom all the same

Melodeon

The OP's photo:

...clearly shows the cable to be PVC stranded cable.

This sort of stuff:
http://www.electricalwholesaler.ie/Products/3-x-25mm-YY-PVC-Flexible-Cable-(Per-1-Mtr)__325YY.aspx

There's no way the drier came out of the factory with this sort of cable.
It's coarse multi-strand cores, while more flexible than solid core cable, are not really suitable for this application where the plug is regularly being inserted and removed. They're simply too strong and rigid, leading to problems with the connections loosening over time.

Proper fine-stranded TRS (Tough Rubber Sheathed) flex would be a much better proposition.

GreenFolder2

Replace the plug with a good quality one and cut the cable back far enough to ensure there is no burnt insulation.

It's likely the socket is damaged as well the pin was that hot. it should probably be replaced.

If you can get one of the MK style plugs with the wrap around posts they are far better for appliances with a constant load. With these the wires are wrapped around a central post terminal and a screw and washer clamps down tightly over them ensuring much better contact.

They're increasingly difficult to find though other than online.

In a normal plug make sure that all the strands of copper are bound together by actually twisting the insulation as you're removing it to ensure they all form together. Cut the correct length and ensure the screw is correctly clamped down across all strands.

Then make absolutely certain it's tight.

Also ensure the fuse is positioned carefully to ensure maximum contact area. it needs to be firmly held in the fuse holder with all of the terminal in contact with the spring. Check this is tight and the fuse holder isn't deformed.

In my opinion this system is an utterly horrible design. despite all the patriotic praise given to the British 13amp plug by uk sparks on forums, it has a terrible tendency to overheat because of the shoddy design of the fuse holder. Moulded on plugs and those MK rewirable ones are a much safer designed as the fuse holder is fixed in position and can't easily be out of line or loose.

You won't notice these problems with a lower power appliance or one that only draws a high load intermittently but with dryers and fan heaters these plugs are simply awful compared to 16 amp continental style Schuko.

Basically just be extremely careful about how you wire the new plug. Just because it works doesn't mean it's not prone to overheating. It's all about maximising the surface areas making contact with the fuse and wire and ensuring the socket is in good condition.

Sleeper12

The neutral was just shoved into the terminal on the plug. It's also damaged where the clamp was. I can only assume that the live was fitted the same way. It looks like the plug was fitted with little care. Looks like a rushed job. Someone might get away with careless work like that on a small appliance but less likely on something like a tumble dryer.

Sleeper12

nkay1985 wrote:

Thanks for the post, not sure I explained the layout correctly. The dryer is in the bathroom. Its power cable is running through a stud wall and plugged into a socket in the adjoining hall.

Not sure if it's legal for dryer in a bathroom. I'm pretty sure anything electric is supposed to have rcbo protection

GreenFolder2

A dryer shouldn't be your typically sized domestic Irish bathroom.

The rules and commonly accepted practice are different in some continental countries but you can't just assume that the same applies here.

A lot of our rules still assume there are no RCD or RCBOs in use and are very conservative.