Grounding electrical dryer

[artemyk]

I just converted the cord of electrical dryer from a four-prong plug to a 3-prong plug. I only connected the three wires from the cord (1 neutral in the middle, 2 hot on the outside). The dryer does work currently.

However, with the terminal block cover off, I can see a green wire running from inside the dryer to the back of the frame, where it is clipped. On the back of the dryer, there is a screw hole marked "Ground Screw". The installation manual says "U.S. electric models are shipped with a ground strap connected from the neutral terminal block post to the frame of the dryer. If local codes prohibit the use of the ground strap, the dryer must be grounded in accordance with local codes." I presume that this is what the green wire is (though I don't see where its connected to the neutral terminal block post... maybe somewhere deeper inside?)

If I'm not mistaken, it is safer to properly ground it. Is this correct? If so, should I screw in one end of the wire into the "Ground screw hole" and attach the other one to a good ground? I have a cold water spigot nearby, but it's painted, so I assume this is no go. Would attaching to the middle screw of a 120-volt outlet work? Also, would any ole (hopefully green) wire work?

Thanks a million

 

[bud16415]

I’m not a pro but for years all the dryer connections were a 3 wire plug and hooked up like yours with a 3 wire pigtail. The installers around here will not hook one up without a 4 pin plug and outlet but still sell the 3 pin pigtails and will leave them with you saying you are on your own with the install.

I personally would leave it with the 3 pin setup unless the dryer outlet was easily converted and rewired with a 4 conductor wire that had a green wire.

Let’s see what the pros have to say.

 

[Kabris]

I always recommend a 4 prong for dryers. Years ago, electricians would use a 3 prong and bond the neutral to ground on dryers. Today that is highly illegal, as neutral and ground must be separate outside of your Main.

 

[afjes_2016]

If you pocket book can handle it the very best thing to do now is to be sure that the line going from the panel to the dryer receptacle is a 3 with ground. 2 hots, one neutral and a ground. This is called a 3 pole 4 wire set up using a NEMA 14 30R.

Any new install of a dryer line must meet this code. Way back before this it was allowed that you can use a service entrance cable (meeting proper gauge of course) which only had 2 hots and a neutral (usually the braided aluminum wire). The principal was basically that the neutral was being used as the ground wire also hence the reason for the grounding strap on the dryer that connected the neutral lug to a ground wire then attached to the body of the dryer. So if there was short the short would travel back on the neutral wire to the panel. They found this was not too safe so the code was revised (don't remember what year) that all new installs of a dryer and even a stove must have 2 hots, a neutral and a ground wire. It is also understood that the dryer is a 30amp circuit and stoves are a 50 amp circuit (in the code book it states minimum of 40amps) but most AHJs will insist on 50amp and that is what I normally do from the start.

If you are converting the line from the panel to a 3 wire plus ground and changing the receptacle and dryer harness you must remove the strap that is connected to the neutral to the ground (on the body of the dryer) and connect the ground from the line to the ground wire on the dryer or directly to the body of the dryer.

 

[user 4883]

water pipes (painted or not) are no longer considered code for grounding.

 

[KULTULZ]

If so, should I screw in one end of the wire into the "Ground screw hole" and attach the other one to a good ground? I have a cold water spigot nearby, but it's painted, so I assume this is no go. Would attaching to the middle screw of a 120-volt outlet work?

Also, would any ole (hopefully green) wire work?

water pipes (painted or not) are no longer considered code for grounding.

Good and pertinent point... :thbup:

 

[afjes_2016]

...However, with the terminal block cover off, I can see a green wire running from inside the dryer to the back of the frame, where it is clipped. On the back of the dryer, there is a screw hole marked "Ground Screw". The installation manual says "U.S. electric models are shipped with a ground strap connected from the neutral terminal block post to the frame of the dryer. If local codes prohibit the use of the ground strap, the dryer must be grounded in accordance with local codes." I presume that this is what the green wire is (though I don't see where its connected to the neutral terminal block post... maybe somewhere deeper inside?)

If I'm not mistaken, it is safer to properly ground it. Is this correct? If so, should I screw in one end of the wire into the "Ground screw hole" and attach the other one to a good ground? I have a cold water spigot nearby, but it's painted, so I assume this is no go. Would attaching to the middle screw of a 120-volt outlet work? Also, would any ole (hopefully green) wire work?...Thanks a million

Wait please! By code you can not have a separate ground wire. It must be contained within the same cable/sheathing/conduit. If you have access to the present cable change it to a 3 wire with ground. 10 gauge wire is required for 30amp for dryers. Get a NEMA 14 30R and change that harness to a 3 pole 4 wire plug (matching the NEMA 14 30 R=receptacle which would now be a NEMA 14 30P="plug") This new code was introduced for a reason; to reduce the chance of electrocution.

No, you don't ground it by connecting it to the screw of a receptacle.

NOTE: Grounding to an existing water pipe is not quite code unless the ground goes from the panel in one continuous wire to the water meter, then jumped over the meter to the incoming main water line. The reason for this now is because many home owners are replacing due to damage or upgrades the existing copper pipes with PEX pipe which of course is non conductive.

Spend a few more dollars and do it correctly.

 

[artemyk]

Thanks @afjes_2016 . I think I understand better now.

I don't want to dig in the wall receptacle, partly because I'm not sure there is even a ground connection there , as would be necessary to switch to a 4-prong outlet.

I ended up running a short piece of 10 gauge wire from the neutral terminal to the chassis of the dryer, i.e. putting in my own grounding strap. I understand this is not as safe as a 4-prong connection, but at least this is the proper way to do a 3 prong connection, right?