Electricians chime in please - 240V wiring mistake?

The HVAC guys should find an outdoor outlet and use an extension cord. How many HVAC tools are not cordless these days?
Vacuum pumps and recovery machines.... off the top of my head.

The lack of 110v receptacles was addressed in the NEC a few years ago....that only helps going forward.
Older installations you do whatever it takes to get the job done.
If it's a residential site, running a cord is an option.
If you are working on a rooftop you are limited on what you can do,
 
jumping the neutral an ground is fine, unless the wire comes from a sub panel with isolated grounds.

your wiring was done to accommodate a 4 prong, when there was only 10/2 ran to the dryer.

there is no issue here, sleep well.
 
jumping the neutral an ground is fine, unless the wire comes from a sub panel with isolated grounds...
I said I was leaving the thread, but now I need to ask: What if the 10/2 Romex feeding the dryer outlet DOES come from a sub panel with isolated grounds? The 10/2 Romex feeding this dryer outlet IS from a sub panel, but I'm not sure at this moment if it has isolated grounds. And by sub panel, I mean the 10/2 is coming from a circuit breaker panel that was added to the house; it is not the main panel.
 
Last edited:
The NEC has been around a very long time.
They try to cover everything that can happen or has happened no matter how unlikely.

As I have said, I'm not a code guy. Guys that do new installations are the ones that are usually on top of that.
I am more of a maintenance type Electrician and became licensed that way.
I do carry a Journeyman's license and have for over 30 yrs.
I spent most of my career working in older buildings where things don't always go the way they should, and you make compromises.

Grounding is not an area you want to compromise.

In the scenario you describe the first thing that comes to mind, if for some reason you lost the neutral (grounded) wire between the sub and main panels, the path of least resistance could be back down the dryer neutral.
With the neutral and ground tied together, the dryer chassis could become energized.

Maybe someone else can come up with other scenarios...that's the one that pops into my mind.
 
Your sub panel should have a 4 wire coming from the main panel. Inside your sub panel you should have a neutral bar and a separate ground bar in this scenario. Check your sub panel and see if 4 wires are coming from your main panel. If it has 3 wires, then the neutral bar/s are "bonded" to the box and you don't have separate ground.
 
For kicks and giggles, here is a picture of the wiring on the rear of the dryer. My wife talked me into ordering a new one from Costco because this one is probably close to its end of life anyway. When I wire up the new dryer, based on how the outlet is wired per the 1st post in this thread, what should I wire differently, if anything?
GE Dryer wiring.webp
 
For kicks and giggles, here is a picture of the wiring on the rear of the dryer. My wife talked me into ordering a new one from Costco because this one is probably close to its end of life anyway. When I wire up the new dryer, based on how the outlet is wired per the 1st post in this thread, what should I wire differently, if anything?
View attachment 254612
Other than missing a strain relief on the cord that wiring is correct along with the bonding jumper. for a home that is wired as yours with a 10/2 if you're not going to rewire back to the electrical panel with a 3 wire having a dedicated neutral, ground and 4-prong dryer receptacle I would suggest purchasing the conversion cord I posted they are code approved and will correct the issue of having a jumper at the receptacle side.

re-install this style receptacle
https://www.homedepot.com/p/Leviton...r-Single-Outlet-Black-R20-05054-P00/311373571

with this adapter

https://journeymanpro.com/products/...33563&pr_ref_pid=4516597661755&pr_seq=uniform
 
Last edited:
Other than missing a strain relief on the cord that wiring is correct along with the bonding jumper. for a home that is wired as yours with a 10/2 if you're not going to rewire back to the electrical panel with a 3 wire having a dedicated neutral, ground and 4-prong dryer receptacle I would suggest purchasing the conversion cord I posted they are code approved and will correct the issue of having a jumper at the receptacle side.
Forgive me if I'm being obtuse, but wouldn't the cable you linked to depend on the wall outlet being correctly wired with 10/3, and the dryer cord being a old style 3-wire?
 
I edited my post hopefully that's more clear.
I looked at the Leviton website for installation instructions for that 3-prong terminal you suggested and it says to attach the white wire to the silver terminal. That wouldn't work with my setup would it? Are they referrring to homes that are wired with the correct 10/3 wire?

I'll admit, I'm out of my depth on this and will most likely need to get my electrician involved.
 
I looked at the Leviton website for installation instructions for that 3-prong terminal you suggested and it says to attach the white wire to the silver terminal. That wouldn't work with my setup would it? Are they referrring to homes that are wired with the correct 10/3 wire?

I'll admit, I'm out of my depth on this and will most likely need to get my electrician involved.
What do you have for wire.. black/white and a bare copper?
 
Vacuum pumps and recovery machines.... off the top of my head.

The lack of 110v receptacles was addressed in the NEC a few years ago....that only helps going forward.
Older installations you do whatever it takes to get the job done.
If it's a residential site, running a cord is an option.
If you are working on a rooftop you are limited on what you can do,
Knowing the dangers and the risks involved is better than blindly following rulebooks to a T if you're a professional in a temporary situation.

If OP buys a new dryer, it'll have a 4-pin connector as per his current plug and outlet. They haven't invented a fifth pin yet, what would it do, supply wifi? :D
 
Back
Top Bottom