Page 1 of 3

BEWARE - why do extension cords melt?

PostPosted: Wed Sep 21, 2016 5:00 pm
by Carbonator
Anyone see the cause?
P3139662 (Medium).JPG

P3139657 (Medium).JPG

P3139660 (Medium).JPG


This still was purchased from a respected HB shop in QLD - not respected by me though!

Re: BEWARE - why do extension cords melt?

PostPosted: Wed Sep 21, 2016 5:25 pm
by Peregian
I am no Sparky but I have seen this type of problem on a hot water service element, the problem was the result of the terminal screw securing the active wire, not being fully tightened.

Over time the wire and terminal over heat and go black, finally the main board circuit breaker trips.

Not saying this is what happened in this case but always double check terminal connections.

Re: BEWARE - why do extension cords melt?

PostPosted: Wed Sep 21, 2016 5:59 pm
by Psykamaholik
I think Peregian is on the money there, wire wasn't twisted properly, screw wasn't tightened properly and came loose over time making a hot joint that resulted in melty-burny badness.

Re: BEWARE - why do extension cords melt?

PostPosted: Wed Sep 21, 2016 5:59 pm
by rumdidlydum
Dry solder joint causing resistance then burning the wire out? :-B

How many watts is the element?

Using a under sized extension cord for long periods could do the same thing :think:

Bet you he wired it up without getting it checked too :violence-smack:

Re: BEWARE - why do extension cords melt?

PostPosted: Wed Sep 21, 2016 6:29 pm
by hillzabilly
I see ,a variety of wire gauges,wires into plug not put under tab so when over tightened cuts thru the wire,sloppy soldering and crimping ,evidence of moisture entering or element seal leaking,scorched terminal were brown wire connects ta relay and very close to boiler,one element wire to close or contacting brass element nut,no RCD on supply power point,wrong size fuse on supply,all = dodgy as ta me .I would ask for details of who did the work ,ie proof of qualification and certification.cheers hillzabilly :angry-banghead:

Re: BEWARE - why do extension cords melt?

PostPosted: Wed Sep 21, 2016 7:27 pm
by Carbonator
In relation to this particular incident, I can't discount the fact that the copper flex inserted into the screw terminal was soldered before insertion. (FFS still builders - this is not a "DICK SMITH" level project!) I'm thinking about resistance of Lead and Tin compared to bare Copper - the gauge of the flex - the resistance and tightness of extension lead terminals and sockets (heat is generated and travels) - oxidation of old electrical gear - just thoughts!

No one has commented on the SSR bolted to the SS body of the still (can the body of a SS still at full noise be an acceptable heat sink - plus help heat the wash (lol)). If not, where is the heat sink? (Yes I know - a good quality SSR like that one de-rates and drops power output to self protect).

Re: BEWARE - why do extension cords melt?

PostPosted: Wed Sep 21, 2016 7:30 pm
by Carbonator
rumdidlydum wrote:Dry solder joint causing resistance then burning the wire out? :-B

How many watts is the element?

Using a under sized extension cord for long periods could do the same thing :think:

Bet you he wired it up without getting it checked too :violence-smack:


Unsure about Watts - didn't ask

All the rest, I concur! The guy was complaining about burning too many extension cords before I looked at it
!

Re: BEWARE - why do extension cords melt?

PostPosted: Wed Sep 21, 2016 7:48 pm
by rumsponge
hmm, quite important to know the watt rating of the element, how do you know that you are not overloading your circuit (3600W element on a 10 A circuit) ? or extension cord as mentioned above ?
If you have a simple ohm meter (multimeter), it is easy to measure the resistance across the terminals ***without power connected obviously***, then use ohms law to calculate Amps at 240V. Amps x voltage = watts
cheers, rs

Re: BEWARE - why do extension cords melt?

PostPosted: Wed Sep 21, 2016 8:35 pm
by andybear
Extension leads will over heat if they are left neatly coiled for any part of the lead. And the more power going through them exaggerates the heating. Leave them in a mess while using them. NO NEAT COILS. :handgestures-thumbupleft:

Re: BEWARE - why do extension cords melt?

PostPosted: Thu Sep 22, 2016 6:28 am
by Aussiedownunder01
Yes they do a few years ago a mate called bring around your arc welder I have a small welding job on the carport
Backed in he said I will pass the cord out the window
Got the job 1/2 done and his wife came running out theres a fire in the kitchen
He had just 1/2 unrolled the lead and left the rest on the kitchen sink

Re: BEWARE - why do extension cords melt?

PostPosted: Thu Sep 22, 2016 10:18 am
by warramungas
Aussiedownunder01 wrote:Yes they do a few years ago a mate called bring around your arc welder I have a small welding job on the carport
Backed in he said I will pass the cord out the window
Got the job 1/2 done and his wife came running out theres a fire in the kitchen
He had just 1/2 unrolled the lead and left the rest on the kitchen sink


I find the extension cord I connect to my element (2000watt) gets pretty hot as it is and is only a couple meters long. That's after a long run (no coils involved).
That heap of spaghetti attached to the boiler looks, well, unprofessional? Could it have been done by an amateur? Maybe the hbs was 'traded in' that boiler from someone else?
Didn't see that controller at first underneath all that wire but buggered if I'd mount one that close to the boiler. Any electronics you care to mention besides thermocouples are usually located as far from heat sources as practical.

Re: BEWARE - why do extension cords melt?

PostPosted: Thu Sep 22, 2016 5:54 pm
by hillzabilly
I used to have two of 10amp by 5mt extension cords with 2000wt elements,they used ta get quite warm as well ,wich was a real worry for me,an electrician friends solution was ta get a 10mt by 15amp extension cord, remove the 15amp plugs then cut it into two 5mt lengths and fit 10amp plugs ,after wich they never got warm or hot again .cheers hillzabilly

Re: BEWARE - why do extension cords melt?

PostPosted: Thu Sep 22, 2016 6:46 pm
by stilllearning
Yup, my 10A cords get very hot, replaced them last weekend with extra heavy duty leads from Bunnings, the ones with 1.5mm2 cores as opposed to 1.0mm heavy duty. Will see how they hold up next weekend.

Re: BEWARE - why do extension cords melt?

PostPosted: Thu Sep 22, 2016 6:57 pm
by coffe addict
The only difference between 10and 15 amp plugs is the earth lug. It can be ground back to the same size as a 10amp if it's only going to be used for 10amp loads. Works great at lowering the temp of the cord.

Re: BEWARE - why do extension cords melt?

PostPosted: Thu Sep 22, 2016 8:20 pm
by Sam.
coffe addict wrote:The only difference between 10and 15 amp plugs is the earth lug. It can be ground back to the same size as a 10amp if it's only going to be used for 10amp loads. Works great at lowering the temp of the cord.


True the plug itself may be the same but the cord it is attached to should be of a heavier gauge.

No one should be condoning grinding back 15A plugs to fit a 10A socket unless you want them to burn their house down :violence-stickwhack:

Re: BEWARE - why do extension cords melt?

PostPosted: Thu Sep 22, 2016 9:15 pm
by bluc
Unless you want a heavier 10a lead but even then should be done by replacing the plugs with 10a ones. What i did so 2000w on a 15a cable just gets warm :handgestures-thumbupleft:

Definately wouldnt recomend running a 15a device on a ground down 15a lead shoved into a 10a socket :handgestures-thumbdown:

Re: BEWARE - why do extension cords melt?

PostPosted: Thu Sep 22, 2016 10:21 pm
by The Stig
Carbonator wrote:This still was purchased from a respected HB shop in QLD - not respected by me though!

I would like a name and shame

Re: BEWARE - why do extension cords melt?

PostPosted: Thu Sep 22, 2016 10:30 pm
by coffe addict
Sam using a 15amp cord on a 10amp circuit can't possibly burn a house down.
As hilzabilly's electrician friend recommended by putting ten amp plugs onto a 15amp cord you have an additional safety barrier not the other way around

Re: BEWARE - why do extension cords melt?

PostPosted: Thu Sep 22, 2016 11:09 pm
by Sam.
coffe addict wrote:Sam using a 15amp cord on a 10amp circuit can't possibly burn a house down.
As hilzabilly's electrician friend recommended by putting ten amp plugs onto a 15amp cord you have an additional safety barrier not the other way around


All good, anything electrical and safety needs pointing out :handgestures-thumbupleft:

Re: BEWARE - why do extension cords melt?

PostPosted: Fri Sep 23, 2016 1:41 am
by hillzabilly
keep it safe guy's.hillzabilly