[tripower]

I have a very typical wall mounted dryer receptacle (4 wire blk, red, wht, grnd).
Double pole 30 AMP breaker at the box.

The black power wire was running way hot. I tested all wires with and without power. when I test the red power wire, power on I get 122 at the receptacle and at the breaker. When I test the black power wire I get 122 with power and around 16/17 volts with power off....????

My gut is telling me I need a new double pole breaker. Thoughts?

 

[brric]

Does the dryer work? Probably phantom voltage.

 

[Jim Port]

Are you referring to temperature? How did you determine this?

 

[Oldmaster]

What is your voltage between the black and red?

 

[joed]

If the wire is hot as in melting, you have a loose connection that overheating.
Your voltages seem correct.

 

[FrodoOne]

Does the dryer work? Probably phantom voltage.

If you used a high impedance digital voltmeter to measure the voltage, "Phantom Voltage" is the most likely explanation.

If you do not have a lower impedance meter, place a "Load Resistor" across the terminals of the meter that you are using when doing such testing.

(A 47 kΩ 1 W resister, or somewhat higher, should be suitable, since dissipation across such a resistor would be less than 0.2 W if you happen to place it across 240 V )

 

[tripower]

What is your voltage between the black and red?

242 at the box and at the breaker.

 

[tripower]

If you used a high impedance digital voltmeter to measure the voltage, "Phantom Voltage" is the most likely explanation.

If you do not have a lower impedance meter, place a "Load Resistor" across the terminals of the meter that you are using when doing such testing.

(A 47 kΩ 1 W resister, or somewhat higher, should be suitable, since dissipation across such a resistor would be less than 0.2 W if you happen to place it across 240 V )

I use an Ideal 61-340

https://www.waytekwire.com/datasheet/316-Manual.pdf

 

[NCmountainCabin]

hmmmm... how did you even originally come to the conclusion or reason to 'test' the 'temperature' of a wire going to/from your dryer?? Did the breaker trip? Is the dryer not performing as it should? Why would you question it if everything is working?

 

[FrodoOne]

I use an Ideal 61-340

https://www.waytekwire.com/datasheet/316-Manual.pdf

And its input impedance is specified as 10 MΩ, which is over 20 times that which I suggested.

joed is correct - as is usual.

It is almost certain that your primary problem is a loose connection or weak spring contacts in the existing socket outlet.

Even if the cause was a loose connection, it is probable that the spring contacts in the socket outlet have been weakened by excess heating.

Replace the socket outlet, before you do anything else.

 

[tripower]

All is fixed and working as normal. Both 240 plug and dryer cable were replaced due to heat damage. Opinions were correct probably a loose connection at the plug. The plug was replaced 15 years ago. i can only assume over time the expansion and contraction due lead to the connection becoming loose. I will keep an eye on it thanks.

 

[udraft]

I know only a little of household electrics, but the wire size was never mentioned. Would not an undersized wire produce extra heat?

 

[NCmountainCabin]

a similar, but different, problem happened to our dryer yesterday...

interestingly, we are two RVs parked on a leased private property, with access to utilities from a former mobile home that has been removed years ago. Along with our other needs for the 50amp outlet for our motorhome, and 30amp outlet for our camper, we also have a 50amp NEMA 14-50 Outlet that provides power to both/either our Nissan LEAF(all battery powered) 240v charging cord, and our 240v clothes dryer.
While neither of these actually have a typical '50amp RV service' 4-wire plug, both are able to make use of the outlet with 'dogbone' type adapters, which create the requirement to 'adapt' from the 240v 4-wire service from the main panel/outlet, to the two differing 240v 3-wire plugs.
The Nissan Leaf Level 2 240v charger and cord use a 3-wire/prong 240v design, and the 'dogbone' adapter simply provides the appropriate 3-wire female outlet to plug into.
The clothes dryer is almost the same 3-wire plug, but the prongs are not the same, which is why it needs it's own 'dogbone' adapter. (some newer dryers use a 4-wire 240v plug/outlet, but that's a discussion for another thread)https://www.amazon.com/gp/product/B07PB5GCTM/ref=ppx_yo_dt_b_asin_title_o06_s00?ie=UTF8&psc=1

I typically keep the Nissan LEAF Level 2 charger cord always plugged in to the 50amp 240v outlet, as the car is used daily, and certainly is used more than the dryer, which is only about once weekly.
When I need the dryer, I simply pull the LEAF adapter/cord from the 50amp Outlet and plug in the dryer's adapter/cord. Easy.

Yesterday, though, when I went to do the laundry, I unplugged the LEAF and plugged in the DRYER.... PPPOOOOOOOPPPPPPP! it immediately POPPED, though I could not determine exactly 'what' had popped, as the sound seemed to come from the outlet, but the adapter and cord was being plugged in at that time, so I really didn't know for sure.
Now, whenever I hear a 'pop'!, I tend to think that a breaker has tripped, but I tried the dryer anyway, to see - nope, the dryer now would not work. So, off to the main panel I went, but the double-pole breaker had not tripped. o.k., so what next?

I decided then to do a test, without my voltmeter, as I could simply plug the LEAF charger back in, and see if the OUTLET still had power ...... yes, it DID. o.k., so what next?

If the breaker had not tripped, and the other adapter and plug worked, it could only be somewhere between the dryer's adapter, plug, wire to the dryer, or the dryer itself.
Hmmmm.... so I though that the 'weak' point here could be the adapter.

These 'dogbone' adapters are quite beefy, well designed, and since they are of fully molded plastic/rubber there's little to 'go wrong'. There's nothing to 'take apart' and look at, other than the mail prongs on one end, and seeing down into the female end to see the brass connectors on the other. What I noticed was water, water dripping out.

o.k., now we're on to something. Water and electricity 'don't mix', as they say, so I came to a quick conclusion that this 'water' inside the female end of the adapter, probably caused a quick 'short', which caused the 'pop'! sound I heard.
Now, if that's the case, why does the adapter no longer work?

I'm not sure if these adapters have any type of 'protection' in these scenarios, but it might be quite possible that they do have built in 'automatically resetting fuses', but it's possible.

I used a hair dryer to dry out the female end as best as possible, and then retried the connection to the 50amp outlet, and voila!, it worked again. Maybe there's an automatic built-in fuse, maybe not, but it worked again after some time, whether my drying helped out or not, I'm not sure, and maybe it just needed 'time'...to reset!

 

[seharper]

a similar, but different, problem happened to our dryer yesterday...

interestingly, we are two RVs parked on a leased private property, with access to utilities from a former mobile home that has been removed years ago. Along with our other needs for the 50amp outlet for our motorhome, and 30amp outlet for our camper, we also have a 50amp NEMA 14-50 Outlet that provides power to both/either our Nissan LEAF(all battery powered) 240v charging cord, and our 240v clothes dryer.

Feeding a 30A clothes dryer from a 50A breaker and plug *is not good*. But its status as a codevio is weird because you are doing it all with plug-in devices.

While neither of these actually have a typical '50amp RV service' 4-wire plug, both are able to make use of the outlet with 'dogbone' type adapters, which create the requirement to 'adapt' from the 240v 4-wire service from the main panel/outlet, to the two differing 240v 3-wire plugs.

The Nissan Leaf Level 2 240v charger and cord use a 3-wire/prong 240v design, and the 'dogbone' adapter simply provides the appropriate 3-wire female outlet to plug into.

That one is fine. It carries 50A to 50A, and ground is present and carried through.

The clothes dryer is almost the same 3-wire plug, but the prongs are not the same, which is why it needs it's own 'dogbone' adapter. (some newer dryers use a 4-wire 240v plug/outlet, but that's a discussion for another thread)

WHOA! RED ALERT! It's not the 30A-50A thing (though that too). This setup is running the dryer ungrounded when you don't have to, because ground is right there. Understand the downside risk. If the neutral wire has any trouble, the chassis of the dryer will be electrified at line voltage. Most ungrounded dryers sit right next to grounded washers, so there's a lot of surface area to get nailed. And I bet it's outside.

Just for safety's sake, completely ignoring the 30/50A issue, I would either convert the dryer to a 14-30 plug (removing N-G jumper) or change that 50A supply breaker to GFCI. And then get a (still illegal) NEMA 14-30 to NEMA 14-50 dogbone from your dodgy Amazon Marketplace supplier.

... Though honestly, if you want to remove the N-G strap from the dryer, and manually run a ground wire to the dryer, that's good enough for the backcountry. Not legal but *anything* is better than whatcha got!

The 30A-50A thing is concerning. The ungrounded dryer is alarming!

I typically keep the Nissan LEAF Level 2 charger cord always plugged in to the 50amp 240v outlet, as the car is used daily, and certainly is used more than the dryer, which is only about once weekly.

Also, those NEMA (non-L) -30 and -50 receps aren't really made for frequent plug interchange. In fact, the rationale that convinced NFPA to keep allowing the dangerous NEMA 10 as long as they did, was (pay close attention here) "It's unlikely to have a neutral problem, because those plugs are only very rarely disturbed".

These 'dogbone' adapters are quite beefy, well designed, and since they are of fully molded plastic/rubber there's little to 'go wrong'. There's nothing to 'take apart' and look at, other than the mail prongs on one end, and seeing down into the female end to see the brass connectors on the other.

Somebody in China got a plastic injection mold. Golfclap. Remember, these are illegal connectors. They do not have UL stamps, *cannot* have UL stamps, won't be sold by Home Depot or other major retailer who are closely watched by FTC, CPSC and the like. Nor can they be manufactured by any competent maker such as Eaton, Leviton etc. due to the risk again of sanctions. So they are sold by crooks dodging the law, like small time garage guys, or beyond legal reach, e.g. China. It gets into Amazon Marketplace because Amazon's lawyers are tougher than FTC lawyers.

And typical China, their stuff looks good, but doesn't reflect on quality. The injection molder can hide a lot of sins!

I for one vastly prefer the ones hand-built by Cooter in his basement. I know he used real #10 wire and proper Leviton sockets and plugs... and if it has trouble I can open it up and fix it.

I used a hair dryer to dry out the female end as best as possible, and then retried the connection to the 50amp outlet, and voila!, it worked again.

I'm glad you're drying again, but for Pete's sake, ground that thing!!

 

[NCmountainCabin]

...the dryer is a 3-wire from the factory, and has been that way from the first owner to now me... the adapter is only used because I have a 4-wire 240v outlet instead of a 3-wire 240v outlet.

the same for the LEAF charger, which only uses a 3-wire cord.

None of this is doing anything 'different' than what it is originally wired for - 'not' making use of an additional wire that neither was originally intended to use makes little difference.

 

[Oldmaster]

Considering that you have the correct receptacle available I'd recommend using a 4 wire cord and seperating the equipment ground and the neutral in the dryer. The NEC no longer allows using the neutral for grounding in this application.

 

[PDX_Dude]

...the dryer is a 3-wire from the factory, and has been that way from the first owner to now me... the adapter is only used because I have a 4-wire 240v outlet instead of a 3-wire 240v outlet.

the same for the LEAF charger, which only uses a 3-wire cord.

None of this is doing anything 'different' than what it is originally wired for - 'not' making use of an additional wire that neither was originally intended to use makes little difference.

Unless I misunderstand something, I would suggest to get a 14-50 plug from Home Depot (something like this for $15) and wire it to your existing dryer power cord. Neutral from the outlet will obviously be terminated at the prong.

 

[Oso954]

Unless I misunderstand something, I would suggest to get a 14-50 plug from Home Depot (something like this for $15) and wire it to your existing dryer power cord.

A 14-50 is a range plug, not a dryer (14-30p)

If his current cord is original factory, I’d suggest he buy a new dryer cord.
https://www.homedepot.com/p/Everbilt-6-ft-10-4-Wire-Electric-Dryer-Plug-61255HD/301864425?mtc=Shopping-B-F_D27E-G-D27E-27_2_WIRING_DEVICES-NA-NA-Feed-PLA-NA-NA-WIRING_DEVICES&cm_mmc=Shopping-B-F_D27E-G-D27E-27_2_WIRING_DEVICES-NA-NA-Feed-PLA-NA-NA-WIRING_DEVICES-71700000034239053-58700003946878363-92700050457563748&gclid=EAIaIQobChMIu7yNtvvo6QIVlxatBh1BwwtdEAQYASABEgLDKPD_BwE&gclsrc=aw.ds

 

[PDX_Dude]

A 14-50 is a range plug, not a dryer (14-30p)

If his current cord is original factory, I’d suggest he buy a new dryer cord.
https://www.homedepot.com/p/Everbil...VlxatBh1BwwtdEAQYASABEgLDKPD_BwE&gclsrc=aw.ds

Your link points to a 14-30 plug with cord -- that is indeed the standard for modern dryers. However, NCmountainCabin stated this:

we also have a 50amp NEMA 14-50 Outlet that provides power to both/either our Nissan LEAF(all battery powered) 240v charging cord, and our 240v clothes dryer.

So, it looks like he is using an adapter to connect his 3-prong dryer plug (6-30? 10-30?) to a NEMA 14-50 receptacle. seharper brought up an issue with grounding, so I was wondering why not solve this haphazard set-up by chopping off whatever 30A plug the dryer has and replacing it with a NEMA 14-50 plug? That would solve the issue with grounding and eliminate the need for that "dogbone" adapter.

 

[PDX_Dude]

OK, I see what's going on! My bad. The dryer is not grounded and is not meant to be grounded when it was manufactured. That's why this dogbone adapter terminates the ground and not the neutral.



What I would do to make it safer is I would get a 14-50 range cord (like this for $25) and then I would manually connect the dryer's frame to the ground wire. A slightly cheaper way would be to buy a 14-50 plug without a cord, connect this plug to the existing 3-wire cord (after chopping off the 10-30 factory plug) and connect a standalone wire (e.g., THHN) between the plug's ground and the dryer frame. It can be ziptied to the existing dryer cord. The latter method is ugly and not really legal, but who cares. Not uglier than the "legal" Japanese grounding set-ups :biggrin2: