Extending/Converting exisiting Nema 10-30R to Nema 14-50R

[FlasherZ]

OK, now I get it.

The AL wiring isn't bad as long as you occasionally (every 5 years or so) open up all your outlet and switch boxes and ensure your connections are tight (since they tend to come loose easier than copper). Also look for any signs of wires burning, etc. Maintenance is a bit higher on it, but it's not as dangerous as an FPE panel or Zinsco panel.

The combination of the two is a bit problematic, as a loose AL connection could cause the same type of problem I had in my home -- tremendous amounts of heat that translates into wires melting -- then you really want your breakers to be working.

 

[jerry33]

Down in the tropical zone = less incentive.

1. I guess you've never paid any air conditioning bills

2. I thought that you were going to go for the mold problem in those hot, humid areas.

 

[Hometheatremaven]

When I removed the faceplate of my existing 10-30R old dryer outlet to insure the wiring screws were tight, I noticed there was a 10/3 with ground in the box. Since the 10-30R doesn't use the ground wire (it grounds through the neutral wire at the breaker box), it was disconnected. I guess that means I could replace the 10-30R with a 14-30R if the ground wire is actually connected to ground.

Not being an electrician, how can I tell with my multimeter if the ground wire is actually connected to ground?

Assuming the ground wire above is connected to ground and I convert the 10-30R to 14-30R, second question:: If I build a 30 foot extension cord, does 8/3 with ground afford me any less power loss (or will it heat up less) than using 10/3 with ground? (remember the incoming wire to the dryer outlet is 10/3 with ground; the total run including the extension is maybe 100 feet).

Thanks.

 

[FlasherZ]

When I removed the faceplate of my existing 10-30R old dryer outlet to insure the wiring screws were tight, I noticed there was a 10/3 with ground in the box. Since the 10-30R doesn't use the ground wire (it grounds through the neutral wire at the breaker box), it was disconnected. I guess that means I could replace the 10-30R with a 14-30R if the ground wire is actually connected to ground.

Not being an electrician, how can I tell with my multimeter if the ground wire is actually connected to ground?

Assuming the ground wire above is connected to ground and I convert the 10-30R to 14-30R, second question:: If I build a 30 foot extension cord, does 8/3 with ground afford me any less power loss (or will it heat up less) than using 10/3 with ground? (remember the incoming wire to the dryer outlet is 10/3 with ground; the total run including the extension is maybe 100 feet).

Thanks.

10/3 is good to about 200 feet total length. 8/3 will give you less voltage drop across the circuit but it will be expensive for very little gain (maybe 1-2V at best).

As for testing your wiring, turn your breaker off, then do a quick voltage test between the neutral and ground wire using a multimeter. Assuming it shows 0 (it should!), do a continuity/resistance test between the two. It should read 0 ohms. That will confirm the wire is at least hooked up, and you could make assumptions based off that if you wanted to. If you want to take it further (I would), find a nearby standard 120V receptacle (probably the washer outlet), turn its breaker off and unplug the washer (to ensure no device on the circuit can cause a voltage or neutral path backfeed), and test resistance using a multimeter between its ground pin and the ground wire in the box behind your 10-30R. It should come in at 0 ohms. If you have a metal cold water pipe available, you could test to that as well. You could feel confident you have a good ground if so.

 

[Hometheatremaven]

FlasherZ:

do a quick voltage test between the neutral and ground wire using a multimeter. Assuming it shows 0 (it should!)

Set to read AC voltage, it reads 0.3 mV

do a continuity/resistance test between the two. It should read 0 ohms.

The meter buzzed and read 0.3 ohms. The manual says "If the circuit resistance is 50 (+/-30) ohms or less, the buzzer sounds continuously to indicate there is sufficient continuity.

test resistance using a multimeter between its ground pin and the ground wire in the box behind your 10-30R. It should come in at 0 ohms. If you have a metal cold water pipe available, you could test to that as well. You could feel confident you have a good ground if so.

I used a cold water pipe to the ground wire; the meter buzzed and read 0 ohms.

Hopefully the above readings indicate the ground wire is effective. Right?

If so, I assume I have 2 options for extending power in the garage. [Well really 4 options because I have to decide whether to create an extension cord or hard-wire through conduit).

1) I could keep the 10-30R and use 10/3 w/o ground to the 14-30R; within the 14-30R I would then connect neutral and ground. (That way I would not be using the ground wire going into the exisiting 10-30R box.) I would then mark the 14-30R "For Tesla use only" and I would remove it whenever we sell the house.

2) I could replace the old 10-30R with a 14-30R, connect the ground wire and run 10/3 with ground to the new 14-30R. The wire would be more expensive and I don't know if it's any better. But reading your previous posts, this is probably what you'd prefer. Right?

Thanks.

 

[FlasherZ]

Hopefully the above readings indicate the ground wire is effective. Right?

It appears so.

If so, I assume I have 2 options for extending power in the garage. [Well really 4 options because I have to decide whether to create an extension cord or hard-wire through conduit).

1) I could keep the 10-30R and use 10/3 w/o ground to the 14-30R; within the 14-30R I would then connect neutral and ground. (That way I would not be using the ground wire going into the exisiting 10-30R box.) I would then mark the 14-30R "For Tesla use only" and I would remove it whenever we sell the house.

2) I could replace the old 10-30R with a 14-30R, connect the ground wire and run 10/3 with ground to the new 14-30R. The wire would be more expensive and I don't know if it's any better. But reading your previous posts, this is probably what you'd prefer. Right?

Thanks.

#2 is my preference, because all new appliances are built for, and prefer, the 4-wire cords, and since you have the ground wire there, it's better to use it and have it available throughout the entire circuit.

 

[Hometheatremaven]

Thanks. You've been a big help.

 

[Markzimzim]

I have a nema 10-30 electric dryer outlet about 20 feet from the garage. I'm planning to replace that outlet with a 14-30 and then use a 14-30 plug, 25 feet of 8 gauge wire and put a 14-30 receptacle at the end of it for the car. Is the L shaped pin in the old 10-30 the neutral or ground? I'm guessing its neutral? VOM reads 120 from either hot to the "ground" and 240 across the two hots. From the breaker box to the existing 10-30 is 10-2 plus ground.. In the new 14-30 plug and receptacle should i connect the existing ground wire to the ground or neutral pin of the new 14-30? The tesla doesn't use the neutral, I believe, only a ground? Am I doing anything stupid here?

 

[Cosmacelf]

Yes, you are doing something stupid there. It sounds like you are trying to create a 14-30 receptacle from a 10-30 receptacle WITHOUT pulling a new wire. A 14-30 receptacle requires four wires, the 10-30 only has three. You would end up with a 14-30 receptacle, a permanent fixture in your house, that wasn't wired correctly. If you were to die of a heart attack, or sell the house forgetting about this jury rigged situation, it wouldn't be a good at all. DO NOT create a permanent plug that isn't wired correctly.

I'm not sure why you want to change the plug from a 10-30 to a 14-30 anyways. Tesla sells a 10-30 adapter. You can make a 10-30 extension cord. Just keep the receptacle as it, make a 10-30 extension cord out of 8 gauge wire and use the Tesla 10-30 adapter.

If this is going to be your permanent charging set up, I'd recommend against it. Extension cords strung through an area that doesn't normally have extension cords are a trip hazard. And knocking loose a 240V 30A connection is just asking for a fire to get started. I would get an electrician to install a proper 14-30, 14-50 or whatever receptacle close to your car.

 

[IMBigg]

I know that this thread is old...but here goes. I have condo that has a 10-30R outlet for a dryer in the garage. Is this the same as 10-30? I looked at the 10-30 adapter on the Tesla website and it looks as if it would fit it perfectly. Thanks!

 

[Cosmacelf]

Yes, it is the same thing.

 

[Cottonwood]

I know that this thread is old...but here goes. I have condo that has a 10-30R outlet for a dryer in the garage. Is this the same as 10-30? I looked at the 10-30 adapter on the Tesla website and it looks as if it would fit it perfectly. Thanks!

A 10-30R is a 10-30 Receptacle (female), and a 10-30P is a 10-30 Plug (male). Yes, the Tesla 10-30 adapter is a 10-30P that will plug into the 10-30R that is an old style dryer receptacle (female outlet).

Good Luck!

 

[IMBigg]

Thanks for the reply, guys! Very helpful.