Most 240v dryers have a 3 prong plug, but actually should have a 4 prong to isolate the neutral from the ground, since the motor and timer usually runs on 120v. Right?
Originally posted by aldav53:
Most 240v dryers have a 3 prong plug, but actually should have a 4 prong to isolate the neutral from the ground, since the motor and timer usually runs on 120v. Right?
All dryers that I have seen up here in Ontario in recent years have a 4-prong plug, for the reasons you state.
I think it's a 96' code, anyways it's fairly recent. All the appliance men now despise us for the NEC's meddeling into this. A large percentage of cord swaps result in the N&G jumper still intact. But sales are up for pigtails!
They are required to be 4 wire systems for new circuits, see the 1999 NEC in Section 250-140. Frames of Ranges and Clothes Dryers.
Sparky,
Let those sniveling appliance men lose a neutral/grd connection in a panel or recp sometime.
Then watch their eyes bug out as they lean their big bare bellies over the dryer and hang on to the washing machine water pipes to reach their beloved 3 wire plug
(I really do hope they're careful)
[This message has been edited by electure (edited 08-22-2001).]
The history on this is pretty pathetic. The 96 code changed a long standing rule, until then the frames of dryers could be grounded with the neutral. Why, you may ask ? It was allowed during WW2 to save copper and not many troubles were reported, finally, based on evidence (people literally dying) it was addressed in the 96 code. Unfortunately, there are LOTS of installations that grandfather. There were too many instances of housewives (or children playing) behind the dryer (cleaning,chasing a ball....) touch the frame of the dryer, and lean into a water pipe, now you're carrying the neutral current. Too darned many were seriously shocked and more than one expired.
LOL !
well they sure snivel up a storm, especially when i get to break the news , which has happened quite often.
It's ironic that the metal saved , which was probably dropped on the enemy during WW2, may quite likley be finding it's way back as those cheapo appliances
Can you confirm that I have interpreted the rules correctly here?
My understanding of the NEC (at least as it was until recetly) is that when a range or dryer outlet was wired directly to the main panel, then only a 3-wire outlet & cord (two hot plus neutral) was needed, the frame being grounded to the neutral.
If the branch was run from a sub-panel (in which N & G are separate), then a 4-wire hook-up was required to provide separate neutral & ground. Correct?
First time I read about this, it took some getting used to, as on our system we never ground an appliance frame to the neutral.
Originally posted by pauluk:
Can you confirm that I have interpreted the rules correctly here?
My understanding of the NEC (at least as it was until recetly) is that when a range or dryer outlet was wired directly to the main panel, then only a 3-wire outlet & cord (two hot plus neutral) was needed, the frame being grounded to the neutral.
If the branch was run from a sub-panel (in which N & G are separate), then a 4-wire hook-up was required to provide separate neutral & ground. Correct?
First time I read about this, it took some getting used to, as on our system we never ground an appliance frame to the neutral.
That is correct.
As of the 1996 NEC, you can use a 3 wire cord for existing installations only ( see 250-140 also 134,138 in the 99 nec) new installations require a 4 wire cord with the neutral NOT connected to the frame of dryers or ranges.
I had heard the statement about the lack of copper during WW2. I have also heard that this requirement was in the code way before the Big One. I will look into my old code books tomorrow to see if I can verify this.
As for the fact that there have been deaths caused by this, I would say - no way -.
If there were deaths that have been caused by this, do you really think it would have taken 50+ years to get the code changed? I have heard of long discussions by the code making panels, but 50 years?
There has been only one death locally that was involving a dryer. The teenage was laying on top of the dryer, and reaching down behind it to unplug the unit. He worked the plug out some, then grasped the plug by wrapping his fingers around the blades, which were still energized. Current thru him to the unit. This would have happened whether the unit was wired via 4-wires or 3-wires.
I honestly believe most deaths have happend because of damaged unit, or by mis-use, like this kid, and not because the unit had only 3-wires.
I like the rule for not having the neutral used as a ground. It is pretty hard telling an apprentice that you do not tie neutrals and grounds together anywhere in a home, but then telling him/her that it is ok to do it on a dryer/range. The new rule makes sense.
Rick Miell
We are all missing the obvious solution. 240 Volt motors and the whole thing goes away.
Less current draw, also.
And 240 volt timer (if not solid state electronics)? And 240 V interior light bulb?
Originally posted by Dspark:
And 240 volt timer (if not solid state electronics)? And 240 V interior light bulb?
Why not? Double pole controls? The electronics is stepped down, anyway.
It still seems better than grounding the neutral at the frame for all those years.
I've never owned, or don't think I've ever seen, a dryer with a light bulb inside. Who makes those?
I think Redsy's got a great idea here.
[This message has been edited by electure (edited 08-30-2001).]
Originally posted by electure:
I've never owned, or don't think I've ever seen, a dryer with a light bulb inside. Who makes those?
I think Redsy's got a great idea here.
[This message has been edited by electure (edited 08-30-2001).]
I just bought a kenmore dryer and it does have a light inside. very nice since I have yet to install the lights in the laundry room!
I think half the dryers have a light bulb in them. This is not a recent innovation. Lights have been in dryers all my life.
I think I 've seen a few with bulbs (but none in my house... my dryer is as old as me!)
But, yeah... Great idea... solves a whole host of problems...
Cheaper cable, cheaper plug, cheaper recept., more "fool-proof"... What's not to like?
A. They would be lot more expensive to design an build.
Thanks, the wife is demanding a
new dryer. The old Kenmore with new parts just won't do again this time ("See hon, works just like new"). A new Kenmore
with a light inside it'll be!