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120/240 wiring for dryer-Please help

Posted by tonistroubles (My Page) on
Sun, Sep 23, 07 at 5:37

Needing clean clothes!! Ok--so the laundry room portion of unexpected remodel is finally complete, along with new washer and dryer. All hooked up, clothes washed, clothes tumbled in dryer, clothes wet.Alas--no heat. Called the appliance store and as I was suspecting, he said it must be in our wiring--which my husband and or a friend or two did. To make sure, I inquired from appliance guy about checking curcuit at receptical with voltage meter (hubby wasn't home and I am a year behind in laundry). So into the outlet I went with my prongs (this is a 3 hole outlet amazingly matching up with the 3 prong plug which was already on the dryer when delivered), anyway, I got a 240 V reading in the 2 slanted prongs but not anything when switching to slanted and L shaped(supposed to get 110-120 according to appliance guy)No breakers were thrown. Hubby returns. "Can't be a problem with the hookup" he says. Upon investigation-he hates it when I investigate his work--I find he did wire the receptical with 10 g 3 wire + ground to a double 30 amp breaker, red and black wire going to each, and the white to the grounding screw things on the right of the breaker box.And the bare copper grounding wire? Just hanging around--Because "there is no place to put a 4th wire in a 3 hole receptical" I am guessing this is the problem, and we are operating without the 120 portion? If so, what is the best solution? Get a new cord with 4 prongs/pigtails or whatever and a mmatching receptical and rewire both of those? The wiring diagram for dryer supposedly ( no it is) in manual. And I guess doing 4 wires to receptical about the same as three. Or is there a simpler answer or even a totally different one? And where does the nuetral white wire go in our curcuit box? ( just so I know what to look for) I really planned on getting an electrician or home inspector here before everything was finalized, but am now thinking maybe sooner than later, as we are adding spa tub etc. Also can anyone reccomend any good sites with pictures? I have a hard time with all the terminology. Sorry this is so long a post, and a million thanks to anyone who takes the time to read it and respond. By the way, could faulty or overloaded wiring/circuits cause a microwave to decrease in power and a refrigerator fan to stop running correctly? And now I am noticing that my lamps blink off a split second when the AC kicks in. And then there are the plumbing issues..but that is for another forum huh? I really did spend hours trying to find all these answers in previous lines--so sorry again, I know they are there somewhere. Humbly, Toni


Follow-Up Postings:

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RE: 120/240 wiring for dryer-Please help

If this is a new circuit (or you modified an old one) you cannot use a 3 prong plug.
New circuits have been required to be 4 wire for many years now (2 hots, a neutral, & ground).
Most likely the receptacle has the ground hooked up and not the neutral.


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RE: 120/240 wiring for dryer-Please help

My best advice is call an electrician. Have coffee and pastry ready when they arrive. Sit them down and explain what's going on - especially the hubby and buddy(s) part. This usually mellows my outlook anyway.

The new installation is required to be 4 wire by code.In the 4 wire configuration the white and bare (ground) wire are both terminated at the ground screw things - called the neutral buss, assuming this is the only panel in the house. At the 4 wire receptacle the 2 outside slots get the red and black. The middle slot gets white, and the half round hole gets the ground. The dryer should have instructions for installing a 4 wire cable.

In a 3 wire installation the neutral (white) wire needs to be attached to the L shapped slot in the receptacle, and attached at the neutral buss in the panel.

If correctly wired, the appliance guy is right about needing 120 volts from either angled slot to the L slot. I'd recheck this again by moving the meter probe around in the L slot to make sure you hit the contact as only one leg of the L is a contact area. The reason I suggest this is it is highly unusual for the motor to operate in a dryer missing the 120 volts.

Given the issues you have you probably already know that under no circumstances should hubby and buddy(s) be allowed to do any wiring on the spa,.

Finally, you sound savvy enough to possibly tackle the dryer issues yourself. Post back if you're game. Hubby can WATCH from a distance.


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RE: 120/240 wiring for dryer-Please help

Good advice form unclebill...except for the last paragraph. If you choose to follow that, your next step should be to pick up the phone and call your lawyer. You're going to need them to defend you in divorce court! Nothing more fragile than the male ego...unless it's a woman's scorn!!


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RE: 120/240 wiring for dryer-Please help

Thanks bill and cobra!Especially for the savvy part, which only came from reading from these posts.And of course I still have questions...It is Sunday and I have no pastries and no electrician--I just want to dry my clothes!I will appologize to hubby and rheem out appliance guy if this all turns out to be dryer malfunction. Uncle Bill--I am going to check the L slot again. The white wire is connected to that and to the neutral bus--so that should be correct? and give me 120 and run the dryer at full speed? Appliance guy was adament that it is common to run but not heat if missing that. Also, please explain how you get 120 V from that test with white basically grounded. Is that picking up the reading of the half of 240-so the current from the one wire to the breaker? HAH! Not so savvy after all:) I do need to back step and say hubby did great job wiring new water heater (many trips to Lowes) OK off to retest and if I find that reading I will then investigate the appliance guy's hookup to the three prong cord they put on--he promised they tested it--wish I had known enough to ask why they would do 3 not 4--they never asked me. Kudos to this site and to all your help. BTW, what about that quetion re. microwave and fridge performance? And I wonder how many divorce lawyers make money from home remodels? Bet it is a bunch!! Toni


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I have Voltage!

Alrighty then! I have current! (or whatever) Thanks uncle bill. I had moved the probe around before but this time I REALLY MOVED IT AROUND!Gosh, only one tiny spot picked up the reading. So I called my husband and appologized profusely for doubting him (even had him doubting it was right, and that is a first) So I know by code 4 wire hookup is required which we can do since he had the forsight and encouragement of Lowes to run the 4 wires in the first place.But now I know it is in dryer side of connection or heating element itself. And I still know we need an electrician before final hookup of spatub etc, hubby already had put in the 2 seperate GFCI circuits in box(with buddy). Our panel is several years old or new after we put pool in we had to replace old one (hired electrician--lots of $)I know, money well spent.Anyway, feeling there still might be problems though doesn't look overloaded and still has empty spot) Now public appology to hubby: sorry, sorry sorry--your buddy isn't a total idiot.Thanks again--and about that micrwave, fridge??


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RE: 120/240 wiring for dryer-Please help

OK. Next step is easy. Just BE CAREFUL and pay attention. You need eye protection (safety glasses)while doing the tests.

Turn off the breaker. Unplug and pull out the dryer and remove the plate that covers the terminal strip where the cable is connected. There should be a diagram that shows how the cable should be wired, but typically there is a terminal strip with 3 connections. The black and red wires go to the outside terminals, white in the middle. If you have a flat gray cable the 2 outside wires go to the 2 outside terminals and the middle wire to the middle terminal. You can verify the middle wire in the gray cable is neutral because it will have "ribs" or small raised lines on it.

If you find the cable hooked up wrong stop, put the cover back on, and call the appliance store. They have a problem. (unless hubby installed the cable - then the appliance store guy gets the coffee and stuff)

Do not touch the dryer with anything but the meter probes while doing the following tests. If the cable appears to be hooked up right, plug the dryer back in and turn it (if you can) so you have access to the terminal strip where the cable connects. Don't attempt this if you have to get in a small place between the wall and dryer to do as there just isn't enough room to work safely. Turn on the breaker. Carefully touch the meter probes to the middle terminal and a piece of bare metal on the dryer. If you read voltage stop immediately something is miswired. If this checks out OK, test the two outside terminals - should be 240 volts or so. Then test each outside terminal to the middle - should be 120 volts.

If you still don't have 120 volts but have the 240 you most likely have a damaged receptacle, or, less likely, a bad cable. If you have the 120 volts to both outside terminals the dryer has issues.

Breaker off, cover back on. So, what's the outcome?


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RE: 120/240 wiring for dryer-Please help

Hi bill--gona check on these things--you give very good instructions! Today was spent with mother-in-law, then we lost a lamb (as in died) so lost interest for the day and didn't care if clothes mildewed even. But now ready to get back on horse--will let you know outcome tomorrow--or come by and you can have the pastries and coffee!


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RE: 120/240 wiring for dryer-Please help

Here is the 3 and 4 prong electrical wiring with pics:
http://fixitnow.com/appliantology/dryercords.htm

Here is a link that might be useful: 120/240 wiring for 3 & 4 prong


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RE: 120/240 wiring for dryer-Please help

Hi. I have a question along the same lines of this thread. I'm moving my washer and electric dryer to a new location. The LG dryer (fairly new) has the three prong cord. I've run 12/3 to the new location. Do I need to change the dryer cord to 4 prong? Or can I just wire it as it is?

And if so, I could have run 12/2 correct?

Thanks,

David


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RE: 120/240 wiring for dryer-Please help

"Do I need to change the dryer cord to 4 prong? "

Yes.

4-wire (hot-hot-neutral-grtound0 has been required for many code revisions for all NEW dryer circuits.

#12 is also a little light for most dryers.

What size circuit do the dryer instructions call for?

#12 can only be used for 20 amps.


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RE: 120/240 wiring for dryer-Please help

The dryer will support 4-wire installation. You'll just have to look at the instructions. Replace the old cord.

And 12 is too light for a 40-amp dryer.


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