Dryer breaker

[dpb]

...

No, that's not entirely so. Service cable with bare ground was allowed for the run from service equipment to the receptacle allowing the uninsulated ground to serve as the neutral providing it (the ground) was also #10 or larger for ranges and dryers.

But from a branch circuit the insulated ground/shared neutral was required to be insulated, yes. But normally 10/3 w/oG was run, not 4-wire.

The height of absurdity in Code (or misinterpretation, I'm not sure, I've not researched to see for certain) was illustrated last summer here when the well pump dropped owing to a failure in a plastic joint (discovered it had been cross-threaded on installation as root cause) and fishing it out ended up ruining existing down-hole wire. They ran

4-wire cable claiming it was required by Code down the hole to a 240V pump with no connection or use whatever for the neutral. Stupid is as stupid does... :(

[Ralph Mowery]

It is not code compliant to install the house wiring for a 3 wire dryer. A new socket must be wired for 4 wires.

As there are many old houses that have a 3 wire socket installed, it is ok to sell a 3 wire cord to match them. I don't know of anyting in the code book that says you have to change the old wiring in the house, just any new wiring must be installed in a certain way.

As someone else pointed out , it is not all that much of a need or safey improvement, but just slightly safer.

Often I think the people in some government safety agency must come up with some kind of idea no matter how crazy just to keep their job.

[trader_4]

+1

Agree, there isn't anything in NEC that says you have to update the wiring.

+1

4 wire is a better way of doing it. My issue, DPB's issue was taking exception to the comment that 3 wire is "very dangerous". If something was very dangerous I'd want it corrected immediately. The 3 wire vs 4 wire is probably lower down the safety list than say AFCI and I don't see people calling existing non-AFCI circuits very dangerous.

[makolber]

Trader I said it ___CAN___ create a dangerous shock hazard.

Most dryers are installed next to washing machines whose cases are grounded . With a 3 wire system, all it takes is for the the neutral/ground connection to come loose anywhere along the line, in the plug, in the panel or in the appliance which is subject to vibration, and the case of the dryer WILL be energized with 120V. Now someone doing laundry with wet hands leans one hand on the washer and one on the dryer and presto....

The dryer in my house is wired with a 3 wire plug and I felt it was too da ngerous so I added a dedicated ground wire to the dryer case.

I belive the NEC made a mistake when they allowed the 3 wire exception and now they have corrected that mistake. This is one case where there actuall y IS added saftey and not just added complication.

Mark

[trader_4]

On Wednesday, September 9, 2015 at 10:39:44 AM UTC-4, [e-mail] wro te:

on to come loose anywhere along the line, in the plug, in the panel or in t he appliance which is subject to vibration, and the case of the dryer WILL be energized with 120V. Now someone doing laundry with wet hands leans on e hand on the washer and one on the dryer and presto....

dangerous so I added a dedicated ground wire to the dryer case.

d now they have corrected that mistake. This is one case where there actua lly IS added saftey and not just added complication.

You're entitle to your opinion and feelings. I've never heard of a single case where someone was electrocuted, seriously shocked, etc. despite this "mistake" being used on ovens, ranges, and dryers for half a century. It's possible for the wire to come undone, but the vast majority are home runs from the receptacle to the panel, diminishing the possibility of that happening.

Apparently the appliance manufacturers agree, because they all provide install instructions for dryer, ovens, etc that show how to hook it up for 3 wire. The dryers I've seen, in fact came from the factory configured for 3 wire and you had to change it to use 4 wire. If it was creating real world serious events, you would think they would be getting their pants sued off.

[gfretwell]

Because they sell more dryers than builders sell new houses.

[gfretwell]

The instructions do say you should use a supplemental ground but that is a violation in itself.

[gfretwell]

Not legally. The 3d wire must be insulated

[gfretwell]

There are different rules for service conductors because they are on the line side of the grounding electrode. I agree there was an exception for SE cable for a dryer but that came with it's own set of rules. We were talking about 10/2 romex

I have not seen much w/o ground wire. It has been in the listing standard since the 60s.

That was misinterpretation.

[Mark Lloyd]

[snip]

I see those cordsets at Wal-Mart. Strangely, not the 4-wire ones.

I needed a 3-wire for my dryer, bought in 2009. This house already had the receptacle for it (likely wired in 1969).

[Sam E]

Voltage drop in that situation (N/G combined, and dryer running) would make the dryer case voltage greater than 0. I doubt it would be enough to qualify as "very dangerous". Probably not even enough to feel if you licked the dryer.

BTW, unless you were doing open-heart surgery in your laundry room :-)

[hah]

[snip]

2-year old child with serious heart condition runs away from hospital, licks detergent spill on dryer with 3-wire cord, found dead with green tongue :-)

[Stormin Mormon]

In the modern post Constitutional north America, legal and safe might not be the same thing, now days.

- . Christopher A. Young learn more about Jesus .

. .

[Stormin Mormon]

And thus was passed the green tongue dryer cord licking detergent spill protection For The Children bill.

[makolber]

It ___CAN___ easily become dangerous if the combined N/G wire suffers an open fault.

Its simple enough to make it better.

Use a 4 wire plug or add a supplemental ground wire.

No big deal.

Mark

[trader_4]

An existing 3 wire circuit is code compliant. Adding a supplemental ground wire is a code violation, assuming the existing circuit is a cable, which is what you have 99% of the time.

[gfretwell]

Not exactly true (see ex-1)

(B) With Circuit Conductors. By connecting to an equipment grounding conductor contained within the same raceway, cable, or otherwise run with the circuit conductors.

Exception No. i: As provided in 250. 130(C), the equipment grounding conductor shall be permitted to be run separately from the circuit conductors.

250.130(C) Nongrounding Receptacle Replacement or Branch Circuit Extensions. The equipment grounding conductor of a grounding-type receptacle or a branch-circuit extension shall be permitted to be connected to any of the following: (1) Any accessible point on the grounding electrode system as described in 250.50 (2) Any accessible point on the grounding electrode conductor (3) The equipment grounding terminal bar within the enclosure where the branch circuit for the receptacle or branch circuit originates (4) An· equipment grounding conductor that is part of another branch circuit that originates from the enclosure where the branch circuit for the receptacle or branch circuit originates (5) For grounded systems, the grounded service conductor within the service equipment enclosure

You are replacing a nongrounding receptacle when you replace a 10-40r with a 14-30r

[trader_4]

On Thursday, September 10, 2015 at 12:42:34 AM UTC-4, [e-mail] wrote :

Interesting, I didn't know that exception existed.

[gfretwell]

It has been around since the 60s and before the rise of plastic plumbing, it allowed just grabbing a cold water pipe.

[Sam E]

[snip]

There's these three connections:

1. 3-wire cable, shared N/G

1. 4-wire cable, separate n and G

2. as #1, but internal jumper removed and dryer grounded separate from cable.

#1 is somewhat less safe. How is #3 less safe than #2? Is it any better than #1?