Dryer outlet question.

[Ichinisan]

I was given a dryer to replace my mother's malfunctioning dryer. Both the old and the new dryer have huge plugs that are not standard 120v. It's a double breaker at the switch box, so I'm pretty sure the existing 3-prong outlet is 240v. The new dryer has a 4-prong plug. Both dryers have screw terminal connections that allow you to remove the cord. Can the three-prong cord be correctly / safely wired to the terminals on the new dryer that came with a 4-prong cord so I can use it with the 3-prong outlet?

 

[Ichinisan]

After some Google-ing, the existing outlet looks like NEMA 10-30.

 

[highland145]

Does it fit the plug? No...new cord. I remember buying my 1st, get it home and no effing cord. Really? Go back to Lowes..."Everyone's plugs are different.....$35 please."

Bastards.

/rant

 

[Ichinisan]

New dryer's plug looks like a 120/240v plug "14-30"

I'm pretty sure I should be able to wire the plug from the old dryer onto the new one. I just need to be sure I'm doing it the right way.

 

[KentState]

Dryers can support either the 3 or 4 prong plug. Pretty common scenario to have to swap out. I think my last dryer had the cord changed 5 times over it's lifetime from moving to different era apartments/homes.

 

[highland145]

Dryers can support either the 3 or 4 prong plug. Pretty common scenario to have to swap out. I think my last dryer had the cord changed 5 times over it's lifetime from moving to different era apartments/homes.

And the terminals should be color coded.


Hell, make your brother do it.:biggrin:

 

[Ichinisan]

From the looks of it, there won't be any ground connection with the NEMA 10-30 cord/plug and outlet. Doesn't sound safe.

 

[natto fire]

From the looks of it, there won't be any ground connection with the NEMA 10-30 cord/plug and outlet. Doesn't sound safe.

While it is not 100% to NEC code, you can tie the EGC (ground) terminal to the "W" pin on the cord, as the neutral of your power service should be bonded to some sort of ground. The NEC is getting really big on keeping EGC and neutral paths separate to the first means of disconnect. The newer dryer with 4 pins was designed to have that fallback to clear faults to a separate grounding path.

It will still be safe with both pins tied to the neutral, as long as you don't lose the neutral some other way, which could cause a fault that makes the case of the dryer have voltage to another "grounded" object, such as a water pipe.

 

[iwajabitw]

All newer 240v lines have a neutral now. So an old 3 prong dryer cord allowing 120v down the black & white wires with a bare ground is acceptable. 4 prongs just add the neutral in.

 

[Ichinisan]

There's a standard 120v receptacle nearby. Could I ground to that?

 

[arkcom]

There's a standard 120v receptacle nearby. Could I ground to that?

The plug is already grounded through the neutral. No need.

 

[natto fire]

All newer 240v lines have a neutral now. So an old 3 prong dryer cord allowing 120v down the black & white wires with a bare ground is acceptable. 4 prongs just add the neutral in.

They have always had a neutral to allow the 120v path for the tumble motor and timer, for US appliances anyways. The 240v is from going hot to hot in a single phase residential service, and is used to get more power, while drawing half the current (compared to 120v), for the heating element.

The 4th prong adds an equipment grounding conductor, which serves as a fault path if the neutral is lost in the machine, which could electrify the metal case. The neutral is supposed to be bonded to the ground in the panel, and as an extra precaution, that ground will be bonded to a ground electrode, or city water pipes.

 

[Ichinisan]

The plug is already grounded through the neutral. No need.

OK. I get that it's not necessary just to make the new dryer work on that outlet which has no ground.

If I wired to the ground on the standard 120v outlet anyway, would I have the safety fallback?

 

[natto fire]

OK. I get that it's not necessary just to make the new dryer work on that outlet which has no ground.

If I wired to the ground on the standard 120v outlet anyway, would I have the safety fallback?

If the other outlet is wired correctly and has a separate grounding path, it would be safer for anyone working on the electric down the road but, at the panel, the ground and neutral should be bonded together anyways, so either way will afford the same amount of safety as far as operation of the dryer.

 

[stormkroe]

While it is not 100% to NEC code, you can tie the EGC (ground) terminal to the "W" pin on the cord, as the neutral of your power service should be bonded to some sort of ground. The NEC is getting really big on keeping EGC and neutral paths separate to the first means of disconnect. The newer dryer with 4 pins was designed to have that fallback to clear faults to a separate grounding path.

It will still be safe with both pins tied to the neutral, as long as you don't lose the neutral some other way, which could cause a fault that makes the case of the dryer have voltage to another "grounded" object, such as a water pipe.

That actually would be 100% AGAINST code. I strongly recommend against doing that. Introducing current into the bonding conductor, and make no mistake it will have current on it from the unbalanced load, is a recipe for disaster. Not only can it reek havoc on your GFCI's ability to determine the mA differences in bond and neutral required for it to function properly, any bonded metal part between the receptacle and the panel that you touch could potentially send current through you if you happen to be touching something with less resistance to ground than your service (this happens in older homes where they were bonded to water pipes that were later replaced with PVC/PEX, or services with high resistance grounding from an apprentice not burying the plate deep enough, etc).
While it's true that the ground and neutral are connected at the consumer's service box, the practical impossibility of current coming back through the neutral to that point, then heading BACK out through the bonding conductor is the main difference.

Point is, if you don't have a neutral, ground, and 2 opposite hots in that box, pull a new wire or get a different dryer.

 

[natto fire]

That actually would be 100% AGAINST code. I strongly recommend against doing that. Introducing current into the bonding conductor, and make no mistake it will have current on it from the unbalanced load, is a recipe for disaster. Not only can it reek havoc on your GFCI's ability to determine the mA differences in bond and neutral required for it to function properly, any bonded metal part between the receptacle and the panel that you touch could potentially send current through you if you happen to be touching something with less resistance to ground than your service (this happens in older homes where they were bonded to water pipes that were later replaced with PVC/PEX, or services with high resistance grounding from an apprentice not burying the plate deep enough, etc).
While it's true that the ground and neutral are connected at the consumer's service box, the practical impossibility of current coming back through the neutral to that point, then heading BACK out through the bonding conductor is the main difference.

Point is, if you don't have a neutral, ground, and 2 opposite hots in that box, pull a new wire or get a different dryer.

Except that he does not have an EGC at his dryer receptacle, so the rest of the house grounding system will not be altered and will not serve as a normal return path. If we were talking about using the ground as a neutral, then yeah, I would advise against that as well. Bonding ground and neutral at the dryer, while not ideal, is not a huge hazard.

 

[Strk]

Go to HD or Lowe's. They sell the cord. You just remove it from the old dryer and attach the new one (it is just attached by screws). They are both 220 lines. When you buy a new dryer and have it delivered (and it's not a gas dryer), the cable isn't attached. They put the cable on that works with the outlet you have. The only concern I'd have is they used the right breaker (30amp).

 

[Ichinisan]

Go to HD or Lowe's. They sell the cord. You just remove it from the old dryer and attach the new one (it is just attached by screws). They are both 220 lines. When you buy a new dryer and have it delivered (and it's not a gas dryer), the cable isn't attached. They put the cable on that works with the outlet you have. The only concern I'd have is they used the right breaker (30amp).

I have the cord from the old dryer. The question was whether I could wire this 3-conductor no-ground cable (NEMA 10-30) to the new dryer that had a 4-conductor grounded cable (NEMA 14-30).

It's done. Dryer works. I guess this old outlet from 1965 has no grounding. I wonder if there's a good way to ground the dryer through another normal outlet in the home or run a wire to a ground rod.

 

[master_shake_]

i can't believe they sell driers without cords now.

it's gotta be an american thing.

nvm i get it.

you guys haven't made the 4 prong standard yet.

usa you weird.

 

[Strk]

i can't believe they sell driers without cords now.

it's gotta be an american thing.

nvm i get it.

you guys haven't made the 4 prong standard yet.

usa you weird.

It is standard, but it's something people don't change, so you can still get the old one instead of replacing it.

 

[natto fire]

i can't believe they sell driers without cords now.

it's gotta be an american thing.

nvm i get it.

you guys haven't made the 4 prong standard yet.

usa you weird.

Ok, sideways panel. Yeah the CEC can be considered tougher than the NEC in some respects, especially with bonding (wish we had grounded yokes on our ganged devices), but we have to account for all the Cletis homeowners that think wiring is super easy. I guess I am done here, since OP seems to have me on ignore. Glad your dryer install went ok.

 

[Belegost]

I have the cord from the old dryer. The question was whether I could wire this 3-conductor no-ground cable (NEMA 10-30) to the new dryer that had a 4-conductor grounded cable (NEMA 14-30).

It's done. Dryer works. I guess this old outlet from 1965 has no grounding. I wonder if there's a good way to ground the dryer through another normal outlet in the home or run a wire to a ground rod.

If the water pipes reach earth close to the hookup point it's possible to ground to the pipe. You can find an appropriate clamp for it at Lowes/HD, just sand the area under it a bit to get oxidation off. Also, make sure it goes on the cold line - grounding to your hot water tank is not helpful.

 

[stormkroe]

It's done. Dryer works. I guess this old outlet from 1965 has no grounding. I wonder if there's a good way to ground the dryer through another normal outlet in the home or run a wire to a ground rod.

That would technically work, though it would break code:
The NEC allows you to install an EGC in a raceway, cable tray, cable armor, or cable sheath. Per Sec. 250-134(b) and Sec. 300-3(b), the EGC must be contained within the same raceway, cable, or otherwise run with circuit conductors.
As natto said, since it's a neutral conductor acting as an effectively isolated ground and not a bond being used as a neutral, the device should be safe (that method for dryers and ranges was allowed up until 96 or 97 I believe)

 

[Red Squirrel]

I'd use the 4 prong plug, you want a separate ground and neutral. The 3 prong is the old style. I think it's to code if it's existing but if you're changing anything you should use 4 prong.

I guess in the grand scheme of things it's probably not a HUGE deal, but I just like to try to do things proper if it's a simple fix.

 

[BoomerD]

I'd use the 4 prong plug, you want a separate ground and neutral. The 3 prong is the old style. I think it's to code if it's existing but if you're changing anything you should use 4 prong.

I guess in the grand scheme of things it's probably not a HUGE deal, but I just like to try to do things proper if it's a simple fix.

Using the 4-prong cord would require substantial rewiring of his house...

1-2-3, just swap the cord. It's easy and safe.

http://www.homedepot.com/c/how_to_replace_a_dryer_cord_HT_PG_AP