Why Am I Melting Extension Cords? - Electrical - DIY Chatroom Home Improvement Forum
Advertisement


Go Back   DIY Chatroom Home Improvement Forum > Home Improvement > Electrical

CLICK HERE AND JOIN OUR COMMUNITY TODAY...IT'S FREE!

Reply
 
Thread Tools Search this Thread
Display Modes
Old 06-01-2015, 06:15 PM   #1
Restoration professional
 
Join Date: Sep 2012
Location: Tulsa, OK
Posts: 150
Rewards Points: 302
Default

Why am I melting extension cords?


In a detached garage, I'm running an infrared heater (1100 watts) which is connected to a 25 foot 12/3 extension cord, which is connected to a 25 foot 16/3 extension cord, into a wall receptacle, connected to 15 feet of 12/2 romex to a junction box, which is then connected to 50 feet of UF NM-B 10 gauge wire running to a 150 watt modern breaker box. The female end of the 16 gauge extension cord melted and won't release the 12 gauge male plug. Also, I've scorched one of those 2-outlet-to-6-outlet power blocks. I know there is more than one weak link here; how does each one contribute?

Yes, an electrician is coming tomorrow. I'm wondering what the group here thinks.
__________________
Tulsa, OK
halliwellc is offline   Reply With Quote
Sponsored Links
Advertisement
 
Old 06-01-2015, 06:39 PM   #2
Member
 
Join Date: Jan 2014
Location: Connecticut
Posts: 1,365
Rewards Points: 127
Default


Sounds like an excellent for starter. Coals should be ready for the burgers any minute now. Personally I wouldn't run any heater on an extension cord for any length of time. Cords have voltage drops . You are suffering voltage drop and too small wire. If you insist on using the cords gets a single continuos 12 gauge cord. Make sure your homeowner insurance is paid up.
jimn01 is offline   Reply With Quote
The Following 4 Users Say Thank You to jimn01 For This Useful Post:
gregzoll (06-01-2015), joecaption (06-03-2015), mae-ling (06-01-2015), sgip2000 (06-03-2015)
Sponsored Links
Advertisement
 
Old 06-01-2015, 07:06 PM   #3
Member
 
dmxtothemax's Avatar
 
Join Date: Oct 2010
Location: Brisbane, Australia.
Posts: 5,448
Rewards Points: 7,854
Default


You need heavier duty extension cords !
I. E. thicker wires !
I would use the thickest lead that you can find/fit.

Also -
are you sure that the recepticule is in good condition ?

it could have dirty contacts.
dmxtothemax is offline   Reply With Quote
Sponsored Links
Advertisement
 
Old 06-01-2015, 07:10 PM   #4
Man of many hats
 
wrangler's Avatar
 
Join Date: Oct 2008
Location: Mississippi
Posts: 558
Rewards Points: 354
Default


Do you understand that the 16 gauge is a MUCH smaller wire than the 12? This is why you are melting it, pulling more amps than the wire is rated for. It is never good practice to run multiple extension cords, though in a pinch I have done it, but only for short periods and when I am physically there. When your electrician is there tomorrow, have him show you how much voltage drop you have over that long run. If you were running a motor powered item, you would have put quite a strain on it. Most power tools (like compressors, table saws, etc.) tell you to plug only into an outlet, not an extension cord for this very reason. Well, that and the fire hazard, of coarse.
__________________
Man of many hats
wrangler is offline   Reply With Quote
Old 06-01-2015, 08:29 PM   #5
Member
 
Join Date: Aug 2009
Posts: 2,141
Rewards Points: 3,396
Default


I looked recently as I was hooking up some 16 gauge fixture cord.

My numbers may be off as I'm not in front of the book. But something to the effect of 16awg being good for 10 amps. Not more than 8 continuous.

Your heater is 9.

The made extension cords usually melt at that point on the female side and on the male side they melt and the forks kinda twist and bend to whete they are attached.

Good quality larger gauge extension cords is what you need or better yet make rid of the cords and wire it with no extension cords if you can
ritelec is offline   Reply With Quote
Old 06-01-2015, 11:08 PM   #6
Member
 
Join Date: Jun 2014
Posts: 36
Rewards Points: 10
Default


Hahaha your funny Cleatis


Living the dream one nightmare at a time.
cad99 is offline   Reply With Quote
The Following User Says Thank You to cad99 For This Useful Post:
InPhase277 (06-02-2015)
Old 06-02-2015, 09:51 AM   #7
Member
 
Join Date: Feb 2008
Location: Atlanta, Ga/Hamilton, Al
Posts: 2,487
Rewards Points: 2,350
Default


The biggest problem is that you need an 1100 watt heater in Tulsa in June.

But if this isn't Cletis, the problem isn't so much the cable size as it is the quality of the connection at the receptacle ends of the cords. There is less than 1 ohm of resistance across the lengths of the two cords, so it isn't the size of the cord that's melting the plug.
InPhase277 is offline   Reply With Quote
The Following User Says Thank You to InPhase277 For This Useful Post:
Nutmegger (06-02-2015)
Old 06-02-2015, 12:13 PM   #8
Restoration professional
 
Join Date: Sep 2012
Location: Tulsa, OK
Posts: 150
Rewards Points: 302
Default


Quote:
Originally Posted by InPhase277 View Post
The biggest problem is that you need an 1100 watt heater in Tulsa in June.

But if this isn't Cletis, the problem isn't so much the cable size as it is the quality of the connection at the receptacle ends of the cords. There is less than 1 ohm of resistance across the lengths of the two cords, so it isn't the size of the cord that's melting the plug.
I called it a "heater" for simplification. It's a tool called a Speedheater that is essentially two quartz IR bulbs in a housing, used to raise the temperature of painted wood and strip paint.

The receptacle-end issue make sense; of course, higher gauge cord can be presumed to come with better quality receptacle. Yes, I will buy a better cord; I'm thinking 50 foot 14/3 cords. And I will protect the cord receptacles from dirt.

Outside the workshop, I often use the tool on 100-year-old houses with sometimes-iffy wiring. I'm going to start using two of them at once, so that's 2200 watts total. Other than testing a customer's receptacles for a real ground wire, and using different receptacles, how can I do this safely?

Another concern: I don't want to use the world's greatest 12/3 extension cord if it will work great and show no signs of overloading, while my tools melt the old wiring in their house. If there's a weakest link, I want the weak link visible. I'd rather my cord fails before their house wiring fails.
__________________
Tulsa, OK

Last edited by halliwellc; 06-02-2015 at 12:17 PM.
halliwellc is offline   Reply With Quote
Old 06-02-2015, 12:43 PM   #9
Member
 
Oso954's Avatar
 
Join Date: Jun 2012
Location: Northern Calif.
Posts: 8,988
Rewards Points: 1,872
Default


With 2 of them, different receptacles isn't enough to prevent overloading. You need to make sure the 2 receptacles are on different circuits. (Assumes 15 amp circuits)
Oso954 is offline   Reply With Quote
Old 06-02-2015, 01:16 PM   #10
Member
 
Join Date: Nov 2007
Location: Nashua, NH, USA
Posts: 8,912
Rewards Points: 3,428
Default


The problem is definitely at the melted plug and receptacle. There is a high resistance point somewhere within, most likely the plug prongs don'e make that good a contact with the receptacle contacts. Any loose connection tends to develop heat.

Another common location for a high resistance point is some of the wire strands breaking, which often happens at the plug or receptacle also. The remaining strands overheat when a high amperage load is put on the cord.

Even high quality cord ends can be compromised by rough treatment.
__________________
Stick to your lawn watering schedule until it really pours. Otherwise the storm might miss and the part that gets watered last (3 days away?) will dry up.

Last edited by AllanJ; 06-02-2015 at 01:43 PM.
AllanJ is offline   Reply With Quote
Old 06-02-2015, 01:57 PM   #11
Member
 
Join Date: Nov 2007
Location: Nashua, NH, USA
Posts: 8,912
Rewards Points: 3,428
Default


The problem is definitely at the melted plug and receptacle. There is a high resistance point somewhere within, most likely the plug prongs don'e make that good a contact with the receptacle contacts. Any loose connection tends to develop heat.

Another common location for a high resistance point is some of the wire strands breaking, which often happens at the plug or receptacle also. The remaining strands overheat when a high amperage load is put on the cord.

Even high quality cord ends can be compromised by rough treatment.

You don't know where the weak spots are behind the walls so it is impossible to set up cords that overheat before the house wiring overheats. Nobody plans for the former. You have to have correctly sized circuit breakers and you have to assume that the wiring will carry the amount of current that the breakers are rated for.

If you wish to you can construct a power strip consisting of a box that holds a cord leading to a plug, a receptacle, and a fuse holder in which you place a fuse of lesser amperage than a circuit is rated for, say, 10 amps.

Lost track of the edits when the 30 minute posting limit expired so the entire corrected post is reproduced here.
__________________
Stick to your lawn watering schedule until it really pours. Otherwise the storm might miss and the part that gets watered last (3 days away?) will dry up.
AllanJ is offline   Reply With Quote
Old 06-03-2015, 05:28 PM   #12
Member
 
Join Date: Sep 2012
Location: Hillsboro, Oregon
Posts: 336
Rewards Points: 332
Default


Quote:
Originally Posted by cad99 View Post
Hahaha your funny Cleatis


Living the dream one nightmare at a time.
Before I saw your comment I was thinking, "Is this Cleatis?"
sgip2000 is offline   Reply With Quote
Sponsored Links
Advertisement
 
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Extension cords. If 14 gauge can supply 15A Sliding Man Electrical 12 12-04-2018 09:39 PM
RV extension cords rjniles Electrical 4 08-11-2012 08:59 PM
making outdoor extension cords for Christmas lights flamtap Electrical 4 01-14-2011 08:21 PM
Extension Cords Types alnoir Electrical 17 10-21-2009 05:37 PM
Extension Cord Safety Ultrarunner2017 Electrical 23 01-20-2009 09:11 PM




Top of Page | View New Posts