Hot Coolant Heater Plug

[WolfgangVW]

Hey all so got cold here today. Had my inline coolant heater plugged in on a timer, ran for maybe 3 hours. Never noticed this before but the 3 prong plug going to my battery blanket and coolant heater seemed hot when I unplugged it from my extension cord. Is this normal or what could be causing this??? It could have been like this before but I don't know why I noticed today! All my cords etc are decent gauge and heavy duty. Thanks in advance!!

 

[eee291]

I charge my lithium battery with 2200W and the plugs on the extension cord get quite warm, like 30-40c.
The wire can handle the current easily but the plugs have a bit more resistance and warm up to the touch, hasn't got me worried because it's laying outside anyways.

 

[9755]

You just need a thicker extension cord is all

 

[Vince Waldon]

Heat comes from resistance, so if the plug is getting warm there's extra resistance, most likely in the form of corrosion at the plug-extension cord connection.

 

[WolfgangVW]

I charge my lithium battery with 2200W and the plugs on the extension cord get quite warm, like 30-40c.
The wire can handle the current easily but the plugs have a bit more resistance and warm up to the touch, hasn't got me worried because it's laying outside anyways.

Ok thanks for the reply !

 

[WolfgangVW]

You just need a thicker extension cord is all

Is there a gauge you recommend?

 

[WolfgangVW]

Heat comes from resistance, so if the plug is getting warm there's extra resistance, most likely in the form of corrosion at the plug-extension cord connection.

This could definitely be my problem. The prongs sit there uncovered all year at the lower grille. Any good tricks for cleaning the corrosion ?

 

[djr6789]

This could definitely be my problem. The prongs sit there uncovered all year at the lower grille. Any good tricks for cleaning the corrosion ?

Get some ACF-50

 

[WolfgangVW]

Get some ACF-50

Ok thanks !

 

[9755]

Is there a gauge you recommend?

Personally I go overkill, but get what you can afford. Big gauge cords are not cheap!

 

[eee291]

I thought the plug got hot not the cable, I don't see the point in investing money where it's not needed.

 

[rwthomas1]

How hot is hot? Slightly warm is OK, and not unusual. Extension cord should be sized for amps being used, and then the length of cord required. There are sizing charts online, go one size larger if near the upper end of size needed. I like "YellowJacket" brand cords, they stay flexible in the cold. RT

 

[WolfgangVW]

Personally I go overkill, but get what you can afford. Big gauge cords are not cheap!

Ok thanks ! It’s a decent gauge right now. Though I bought a new timer, it’s different than my old one. I wonder if somehow the new timer could cause an issue ? Interestingly enough the new timer broke so i had it plugged in for about 5 hours straight into the wall, and the plug wasn’t hot when I unplugged it. So no sure if it’s the timer or just the fact it ran long enough for the thermostat to shut off the heater for a bit.

 

[WolfgangVW]

I thought the plug got hot not the cable, I don't see the point in investing money where it's not needed.

Yes it is the male plug end that sticks out of my lower grille that gets hot

 

[WolfgangVW]

How hot is hot? Slightly warm is OK, and not unusual. Extension cord should be sized for amps being used, and then the length of cord required. There are sizing charts online, go one size larger if near the upper end of size needed. I like "YellowJacket" brand cords, they stay flexible in the cold. RT

Awesome ok I’ll check online. One time it was really hot. Like I pulled my hand away as it surprised me but I didn’t get burned or anything. The other time it was fairly warm but you could touch it. And as in my above post one time it was cold ...

 

[djr6789]

Honestly I wouldn’t bother changing the gauge of the cable if it’s only the plug that gets hot. I would Clean the prongs on the plug and the socket! Corrosion=resistance and resistance=heat! If you have a temperature gun a measure the temp of the plug and cable and then clean them! Hopefully you should see a massive drop in the heat.

 

[Vince Waldon]

Every few years I just cut the female ends off my blockheater cords and replace 'em... no real way to clean inside and they corrode over time.

 

[djr6789]

Every few years I just cut the female ends off my blockheater cords and replace 'em... no real way to clean inside and they corrode over time.

Treat it yearly with acf-50

 

[rwthomas1]

If the male plug coming from the heater is getting that hot it is probably toast. Corrosion will make it's way up the conductors under the insulation. You can cut the male plug off and re-terminate as long as you understand that ANY replacement plug will NOT be even remotely as corrosion resistant as the molded plug. Hosing down the wires with ACF50, CorrosionX, Boeshield, etc. will go a long way in preventing moisture wicking into the wires. Or replacement wire back to heater unit. Drench plug a couple times a year with one of the above, and it won't happen again. RT

 

[WolfgangVW]

If the male plug coming from the heater is getting that hot it is probably toast. Corrosion will make it's way up the conductors under the insulation. You can cut the male plug off and re-terminate as long as you understand that ANY replacement plug will NOT be even remotely as corrosion resistant as the molded plug. Hosing down the wires with ACF50, CorrosionX, Boeshield, etc. will go a long way in preventing moisture wicking into the wires. Or replacement wire back to heater unit. Drench plug a couple times a year with one of the above, and it won't happen again. RT

So my setup is I have a battery blanket, inline coolant heater, and oil pan heater. I have a really heavy gauge plug with the male end sticking out my lower grill, it runs up to a three female end under my hood. I can plug and play whatever I want to use. Currently I have my battery blanket ( 80w I think ) and my inline coolant heater (1000w) plugged into the small three input " extension cord" under the hood with the male end sticking out my grille, which is where I plug in my extension cord which goes into a timer and into the wall. When I want to get rowdy and it's like -35C I'll add the oil pan heater (250w I think) to the mix. Everything under the hood is out of the elements. The male end sticking out the grille is completely exposed.

The inline heater is functioning as after plugging in for a few hours at -23C the glow plugs don't even have to come on. Tested the oil pan heater and battery blanket when I winterized and they functioned great. I'm going to keep monitoring. It's weird how this hot plug seemed to only happen , or the worst with that new timer. You know what In saying all this I'm going to plug that thing in straight to the wall right now and feel the plug in an hour or so. I'll report back!

 

[WolfgangVW]

Hmm so after almost an hour the plug is totally cool to the touch ??

 

[rwthomas1]

Well the good news is it's either the splitter cord that goes to the three heating elements or it's the cord. Either one is probably cheaper and easier than any of the heating element cords. If it ain't heating up plugged directly to the wall, it's the cord. Corroded or too small a gauge for the load.

RT

 

[WolfgangVW]

Ok thanks. And thanks for all the posts back. I’ll try a few of these remedies and post an update down the road !

 

[wonneber]

Well the good news is it's either the splitter cord that goes to the three heating elements or it's the cord. Either one is probably cheaper and easier than any of the heating element cords. If it ain't heating up plugged directly to the wall, it's the cord. Corroded or too small a gauge for the load.

RT

Please correct me if I am reading this wrong but are you running 3 physical heaters from one extension?
Do you know how many watts each heater is rated at?
A 120 volt home outlet is usually a 20 amp circuit and can run one 2400 watt heater.
A 80% total usage is a safety factor I was told by the licensed electrician where I was working.
1980 watts total.
If 'the splitter cord that goes to the three heating elements' is getting hot it's the weak link and exceeding it's capacity.
This also would call for a 12 gauge extension, not the usual 14 gauge one's I see in many stores.

 

[Vince Waldon]

Betcha the OP is on a 15 Amp circuit, and at 80% 1500 watts is the most one should ask for. Add a long extension cord, particularly if not heavy gauge, and it should be derated further.

But... that's not what's causing just the plug to be hot.

 

[rwthomas1]

His earlier post stated 1000watts for heater, 80watts for battery blanket, and 250watts for oil pan heater. That's about 90% of the capacity of a 15amp circuit. Yes, 80% continuous is what is recommended for any circuit. But OP stated he rarely ran the oil pan heater, so that is well within the recommended limits. Even so, with a high quality 12gauge cord, and a short run, it shouldn't be a problem. The area that is heating up is the problem, the resistance is there.

RT

 

[WolfgangVW]

His earlier post stated 1000watts for heater, 80watts for battery blanket, and 250watts for oil pan heater. That's about 90% of the capacity of a 15amp circuit. Yes, 80% continuous is what is recommended for any circuit. But OP stated he rarely ran the oil pan heater, so that is well within the recommended limits. Even so, with a high quality 12gauge cord, and a short run, it shouldn't be a problem. The area that is heating up is the problem, the resistance is there.

RT

Please correct me if I am reading this wrong but are you running 3 physical heaters from one extension?
Do you know how many watts each heater is rated at?
A 120 volt home outlet is usually a 20 amp circuit and can run one 2400 watt heater.
A 80% total usage is a safety factor I was told by the licensed electrician where I was working.
1980 watts total.
If 'the splitter cord that goes to the three heating elements' is getting hot it's the weak link and exceeding it's capacity.
This also would call for a 12 gauge extension, not the usual 14 gauge one's I see in many stores.

Betcha the OP is on a 15 Amp circuit, and at 80% 1500 watts is the most one should ask for. Add a long extension cord, particularly if not heavy gauge, and it should be derated further.

But... that's not what's causing just the plug to be hot.

Hey thanks for the replies. So this is interesting because when I added my coolant heater i did some research and yes I discovered I didn’t want to be over 80%. So all 3 plugged in put me at 1330w. It’s on a 120 v 15 amp plug so 1800w. So I’m under my 80%. As posted before I’ll rarely at the oil pan heater to the mix as the coolant heater works so well.
The 3 way splitter is pretty heavy duty and my extension cord is actually a 12 gauge cord. It’s not overly long , just long enough I can plug in my car if I pull it on forward or backward.
So I haven’t had the problem with the hot plug again. I have a sneaking suspicion it’s one of my inlets on my 12 gauge extension cord ( it’s one of the ones with 3 plugins , not to confuse with my 3 inlet one under the hood lol). I think there’s corrosion in the one inlet causing resistance.On a whim I decided to use the other side and a different inlet and haven’t had the problem since. I haven’t had time to look or test but I’m betting that’s my issue. Thanks again for the posts and information ! I will post back with what I discover.

 

[rwthomas1]

I usually base my math on 110volts nominal. So a little lower on the threshold, a little more margin. But you are on the correct part


RT

 

[WolfgangVW]

I usually base my math on 110volts nominal. So a little lower on the threshold, a little more margin. But you are on the correct part


RT

Yeah that makes complete sense !