30 amp power cord overheating

[deepdoc1]

I've searched around and can't find the info I'm looking for. I have a 30' 30-amp shore power cord hard-wired to a built-in Surge Arrest, and I frequently use a 30' 30-amp extension cord for yard camping. I've noticed the prongs starting to show signs of overheating where the shore cord and the extension are connected together.

I occasionally run the AC, and may sometimes forget to switch the water heater to propane while running AC, so that may be the culprit. I am thinking I need to replace the cords, but I had an idea I need to check out with the wizards here.

My thought is to make my own upgraded cords using two 30' lengths of 8/3 or even 6/3 (or 6/3 - 8/1 if I can't find 3 conductor) SOOW from HD or Lowes. My thought is that the OTC 30-amp cords are at their limit with 10 ga, so going fatter may reduce heating issues.

Most other best practices are being followed (for the most part) such as making sure the power is off at the post before connecting or disconnecting the cords, etc. Thoughts? Tips?

Thanks!

[westend]

This page has more information than you probably ever wanted to know, and passes my sniff test.

Good article on the role of dielectric greases and connectors. I'd only differ with the author on the role of metal-added compounds for thermal dissipation. IMO, Arctic Silver has a place for use but not in the context of RV connections.

[MEXICOWANDERER]

This is where I must strongly disagree. If the contacts are discolored, they are annealed. You can shine them until they are like mirrors, but without a tight fit, armageddon is inevitable. Especially if operated near max capacity. You cannot buff resilience back into a spring. Contacts have "wipers" whose actions vanish forever if overheated. Too many times I have seen campers spend hours disassembling and shining contacts only to see disaster arrive a few weeks more. You might get away with shining up a plug if it isn't burned too bad, but not a socket. Once overheated it has had the course.

NOTICE THE WORD "DISCOLORED" It has significant meaning here

[deepdoc1]

Ok, I guess you guys saved me some bucks for fatter cables. I just ordered up some Progressive replacement plugs and will do a proper job of replacing the burnt ends, making sure to cut back to good copper. Thanks everyone!

[GordonThree]

ktmrfs wrote:
wire gauge is NOT your problem if the prongs or connector are showing heat fatigue. It's likely either a worn out or poorly designed socket and/or plug.

The easiest cure is to cut off the offending ends that are showing heat fatique and replace them with high quality plugs and sockets. Marinco is one such brand but there are others as well.

x2

even just dirty contacts inside the outlet can cause overheating. instead of the full width of metal making electrical contact, perhaps only a small part is, and that causes heating.

Before cutting off ends, try spraying contact cleaner into the outlet (breaker off!) and also spray some on the plug... scrub up the plug contacts with one of those green abrasive kitchen pads or steel wool, I wouldn't use sand paper or emery cloth, it's far too agressive

[MEXICOWANDERER]

Gotta little tip for unbelievers...

Remove battery cables from battery posts

Shine up both post and lugs

GOB ON the silicone grease especially where posts meets lugs.

Reassemble

Place left hand under to support your jaw.

Twist key to start engine

Life is funny. Reality versus theory. Theory loses 100.00% of the time.

[DFord]

I used to have trouble with my 30amp plugs getting hot, melting and turning black. Then I started using dielectric grease on all my connections. It's the best stuff ever for your plugs. I haven't had any problems since. I usually push a little in the park's socket before I plug in. After getting it all over the male plug, I use a small child's sock over the end off it when unhooking and coiling the extension up to keep it clean. This has worked really well for my for several years now.



I buy it at Autozone

[DrewE]

Dielectric grease is an insulator, but in the process of plugging in the connection it gets wiped out of the way of the actual contact points (assuming it is being applied and used properly).

Conductive materials or greases with suspended metal ("conductive grease") have their own problems, not the least of which is the possibility of creating a current leak or even short circuit.

This page has more information than you probably ever wanted to know, and passes my sniff test.

[pianotuna]

I thought silicone dielectric grease was not a good conductor?

[MEXICOWANDERER]

Any, meaning the tiniest hint of overheating at the plug or socket pins, the socket or plug must be discarded and replaced with a new plug or socket. These connections rely utterly on spring tension to make a secure electrical connection.

When they overheat then cool the spring tension disappears and limp noodle syndrome sets in. This is caused by ANNEALING which can happen to copper and brass.

When you strip the insulation of the black, white & green pigtails, the wire can be scraped to bright copper if black or violet color. But you cannot use stripped pigtails of the wire is green or dull red. Red means red, not aged copper. When in doubt bend the strands, if they bend like cooked spaghetti then you have to re-cut the cable further back and try there.

Overheated plugs and sockets CAN NOT BE SALVAGED. Replace them as a mating pair.

Assemble using silicone dielectric grease. De-Oxit D100 does not last as long as Silicone grease, even the hideously expensive L-De-Oxit does not protect as well or last as long as a glop of silicone grease. I own all this stuff and have learned about them via The School Of Hard Knocks.

If you try and cheat on doing the cable repair correctly, you are going to pay a truly unpleasant penalty later on. Also from the school of hard knocks.

[Chris_Bryant]

Another vote for it being the connectors, and not the wire gauge (which would heat the entire cable).
I really like the Progressive Industries TT30R and TT30P connectors, much better quality than any others I have seen. Remember on the molded plugs the terminal is just press fit on the end of the wire, and if you overheat those once, they continue to deteriorate.

[Boon_Docker]

The male and female plugs are either oxidized or not making a firm connection. Replace both with good quality plugs and that problem should go away.

[pianotuna]

Get some deoxit. Tread the plugs. If they are bad--then replace--and treat with deoxit.

[wildtoad]

I've had issues running extension cords for our old 30 amp MH, with plugs overheating even when connected to 30 amps at a campground or at home. I wonder if its caused when the plugs are on wet grass or out in the rain? May need to take steps to keep them dry. Just my thoughts.

[ktmrfs]

wire gauge is NOT your problem if the prongs or connector are showing heat fatigue. It's likely either a worn out or poorly designed socket and/or plug.

The easiest cure is to cut off the offending ends that are showing heat fatique and replace them with high quality plugs and sockets. Marinco is one such brand but there are others as well.

[deepdoc1]

Oops, should have included that bit. The outlet I'm plugging into is a 30 amp RV box I installed myself, and I did use 8 ga wire for the run from breaker box. It has been used for a year or so, and has been rock solid and passes the SurgeArrest tests.