Any Electrical Guru's here???

2716 Views 24 Replies 8 Participants Last post by sben763, May 1, 2012

TableSyrup

Discussion Starter · Apr 27, 2012

Could use a double-check/verification

Ok, so I have an older Vastex Dri-Box I picked up that is 240V

The conveyor heater is the older 3 wire setup.

I ran a 4 wire 240 Outlet per code.

So. The conversion....

My 4 Wire is:

Ground - Bare Copper
Neutral - White
Hot - Red
Hot - Black

The Dryer is:

Ground - Green
Hot - White
Hot - Black
(Both white and black are hot, Right??)

So..... For the dryer, I should replace the plug with a 4 Pin, and wire as follows:

Green to: Ground & Neutral Tied (Or just stab to one or the other??)
Dryer White Hot to: say, Red
Dryer Black Hot to: say, Black
(or vice verse on the hots, shouldn't matter?)

Right?

Or, I could do it in the panel on the dryer, but then I'd have to buy a cord.... so I could just do it in the plug right?

I've never understood the purpose behind the ground plus neutral, since they tie together at the panel anyway....?
am I missing something???? Just for additional shielding/grounding?

Appreciate any help....

Thanx guys

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1 - 20 of 25 Posts

superD70

· #2 · Apr 27, 2012

Quite a lot of misconception on this. 240V is two hots and a ground. Neutral is for 110V. You have four wires on a range or a dryer because there are 110V components (clock, lights, etc) in the appliance as well as 240V components (the heating elements).
never hook neutral to a ground other than inside your breaker box

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tcrowder

· #3 · Apr 27, 2012

Do yourself a huge favor and hire a pro to do the electrical work. You wouldn't ask a mechanic to fill a cavity would you?

ScreenFoo

· #4 · Apr 27, 2012

Depends on how handy they are with a Dremel...

D hit it right on the head--the funny thing about this is, on our dryer there's actually a 2:1 transformer for the 110 stuff--go figure.

sben763

· #5 · Apr 27, 2012

A neutral and ground do tie together at the electrical panel but the neutral Acually will flow returning electricity and a ground does not. There for a neutral is always a coated wire. The neutral also keeps the balance point between the 2 hot legs. With pure 240v equipment it is not needed but take you cloths dryer. The motor run off of 120v and the heating element at 240v. For years the ground has been used as a neutral on the older dryers and on the newer dryers they are still a provision for a 3 wire system to be used which will use the ground as a neutral.

Ok with all that said if your dryer doesnt have a neutral it is probably a 240v only or is using the ground as neutral. Most older equipment can be upgraded to a 4wire system if I has a 120v motor for the conveyor. With the age of the dryer you can hook up 3 wire and still stay within code.

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ScreenFoo

· #6 · Apr 28, 2012

But wouldn't it be an improperly wired unit if it uses the ground as a neutral?

It was always my understanding that the reason the ground doesn't need to be insulated is because it's not supposed to carry current--unless something is going wrong in the circuit.

(Should make a disclaimer posting in this thread--I am no guru of anything

)

sben763

· #7 · Apr 28, 2012

This is correct. Ok so anything using 240v like a heat panel all the energy and because both legs legs are being used no need for the balancing leg (neutral). So no voltage is carried in ground. On a standard cloths electric dryer the the motor is 120v and on a 3 wire system this is exactly what happen the neutral is the ground.*** DO NOT TRY THIS*** If you disconnect the ground on a 3wire dryer the motor will not work. If you were touching the dryer when the start button was pushed you would get shocked and if you were in bare feet the motor would probably start. ****DO NOT TRY THIS **** so this is why there is now a 4wire system on all 240v appliances and I believe is acually part of the NEC now and wasn't till sometime after 2000. I live in a location were there are 3 locatites for building codes. City,W city, and county. Up until was required by NEC only 1 required 4 wire.

The neutral leg croded on a electrical panel on a building that I do work for. I had heard of this but this was first time had seen it. When some one would kick on a dryer or any thing with a 120v draw. Some lights would go dim and some would get really brite and some even blew. I put
my meter on panel and when a motor would kick on voltage would go way down 80v where the applice was and on the other side of panel it would go up to like 160v. With the neutral fix it wouldn't go up or down by more than a few volts.

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TableSyrup

Discussion Starter · #8 · Apr 28, 2012

Ok... so as I understand it then, the only things that use a 4 wire 240v are those that use BOTH 120 AND 240 ???

So, in a 4 wire 240V:
the 240 stuff uses HOT/HOT/GROUND (in case of issue)
the 120 stuff uses HOT/NEUTRAL/GROUND (in case of issue)
Correct??

My conveyor has two plugs, one 3 wire 240 for the heater, and one 3 wire 120 for the belt.

I wired up a 3 wire outlet. All's well.
I also wired up 2 dual gang boxes for 120 20A since I needed more.

Now I'm curious though.
Could I switch the outlet to a 4 wire, swap the heater cord to a 4 wire, and then connect the belt to one of the hots, neutral, and ground, and the heater to both hots and ground???

Then I could have just the one plug, rather than two separate plugs. Would be much cleaner, and more convenient.

Would it matter which hot was used???

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sben763

· #9 · Apr 28, 2012

yes you could but your 240v breaker is probably 40-60 amp and your 120v is likely 15-20 amp so your electrical wouldn't be protected properly. My dryer has a single 50amp circuit but in the control panel it has separate fuse block for all the 120v stuff. You would need to fuse were your 12ga wire starts.

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TableSyrup

Discussion Starter · #10 · Apr 29, 2012

@sben763

So, the speed control box for the motor says 1A, and it is DC... so it converts the AC to DC.... obviously a transformes is in the speed control box, but that circuit should draw more than 1A right?

I'm sure they figure it would be plugged in to at least a 15A circuit. Currently I have it on a 20A.

So, the heater is on a 30A....

If I did wire it up on one hot, and throw a 15A fuse in line on the hot, it should be OK?????

Does it matter which hot I use?

I don't fully understand the push pull on cycle.... 60 HZ....
The 240 completes through two hots. Is there any kind of polarity involved??? Because it's AC I think not. so it shouldn't matter which hot I pull my 120 from correct?

So if I understand correctly, I could change the 3 pin outlet for a 4, take the heater from the HOT/HOT/GROUND, and the conveyor from HOT(Fused 15A 120V)/NEUTRAL/GROUND ?????????

I would really like to have it on just the one plug. That would be great.

I should add, the dryer says 10A.... and it's on a 30.
I don't even see 10A 240 breakers anywhere.
Should it not be on a 30?????

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mailman

· #11 · Apr 29, 2012

I am a little confused on your dryer, do you have a seperate plug for your heater and conveyor, or one single plug for both. I have a little buddy dryer that is 220 , no neutral. I ran 12-2 with ground, using the neutral as a hot and black as hot with a 20 amp double pull breaker. Mark

TableSyrup

Discussion Starter · #12 · Apr 29, 2012

mailman said:
I am a little confused on your dryer, do you have a seperate plug for your heater and conveyor, or one single plug for both. I have a little buddy dryer that is 220 , no neutral. I ran 12-2 with ground, using the neutral as a hot and black as hot with a 20 amp double pull breaker. Mark

two plugs

1 for heater - 3 wire 240v, hot/hot/ground
1 for belt/conveyor - 3 wire 120v, hot/neutral/ground

mailman

· #13 · Apr 29, 2012

I understand, getting it wired for just one plug is beyond me. Sorry i can't help with that . Mark

sben763

· #14 · Apr 29, 2012

TableSyrup said:
@sben763

So, the speed control box for the motor says 1A, and it is DC... so it converts the AC to DC.... obviously a transformes is in the speed control box, but that circuit should draw more than 1A right?
the controls a only take 1a DC you would add that to what your motor pulls to find your total amp draw if your wire on the plug from the box is 14ga it's 15a. If its 12ga then 20a. Standard outlet in a home are only 15a but commonly are on a 20a breaker cause 12 ga wire is run to then. .

If I did wire it up on one hot, and throw a 15A fuse in line on the hot, it should be OK?????

Yes but I would mount it in the control panel so it can be reset from the outside like a push button on a power strip. Some home stores sell these
Does it matter which hot I use?
no it does not

The 240 completes through two hots. Is there any kind of polarity involved??? Because it's AC I think not. so it shouldn't matter which hot I pull my 120 from correct? either hot will work

So if I understand correctly, I could change the 3 pin outlet for a 4, take the heater from the HOT/HOT/GROUND, and the conveyor from HOT(Fused 15A 120V)/NEUTRAL/GROUND ????????? yes you can do this just remember that the wire going into breaker or fuse (you add)on the input side of size must be 10ga if your 240v is 30a breaker

I would really like to have it on just the one plug. That would be great.

I should add, the dryer says 10A.... and it's on a 30. How many panels are in dryer and what wattage. My guess is that the 10a is for the 120v side. Is the wire going into the main wiring block 10g or bigger then your 30 is ok.

Add info in bold above

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sben763

· #15 · Apr 29, 2012

If you had 1 2000 watt panel at 240v you would have 8.33 amp per panel. To test what watt panel you have take an ohm reading on leads to heater. A 2000w heater will have 28.80 ohms a 3000w 19.9 ohms a 4000w heater will have 14.40 ohms. This is for 240v panels

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cyclesurgeon

· #16 · Apr 29, 2012

Does anyone smell meat cooking?

Table? You OK buddy?

TableSyrup

Discussion Starter · #17 · Apr 29, 2012

I'm good. Hahaha. I've wired ... Well... Rewired most of my house.

I just always quadruple check myself on stuff I'm not used to.

I don't do a lot of stuff with 240... And I'm only 31.

My oven and clothes dryer are both 4 wire, which is what I'm used to with 240, so the 3 to 4 thing threw me

House isn't crispy... Yet

ScreenFoo

· #18 · Apr 29, 2012

Honestly, I think the best part about wiring anything is asking whoever's around to hold the fire extinguisher. Last time I was wiring up mercury contactors in the dryer--told the boss to grab the fire extinguisher because I was throwing the breaker , he started laughing. I just looked at him deadpan.

(I have too much fun sometimes)

But seriously, I don't care how many times you've done it, you can still screw up. If you hang out with those 'licensed electricians' for any period of time, you know they are just in better practice taking shortcuts.
I know a few who buy their screwdrivers at harbor freight--cause they arc weld one every couple of months.

TableSyrup

Discussion Starter · #19 · Apr 30, 2012

Yeah, I'm gonna wire the 110/120 off the 240 feed tonight....

Power runs in to the electrical box for the heater, and the first thing it hits is a 10A Breaker.

Power runs in to the speed control box for the belt, and the first thing it hits is a fuse.

So.... if I pull my 120 from a hot before the breaker, I should be fine.

That puts it on a 30A breaker at the panel, but it is fused at the control, so I should be ok eh?? I guess the proper way to do it would be to put 10AWG on it though huh???? just in case of a short???

I'd really like to pull it after the breaker for the heater, but I'd have to swap out the 10A Heater Breaker for a 15A?.... I think?

On the motor speed control it says 1A,
on the motor itself it says 3587, Vastex, 90 VDC, .25 (clearly a decimal), 11RPM, 1/30 HP
I assume the .25 is A. Really?? 1/4 Amp for the motor???
Fuse on control is labeled 250v 1A.

So, with the heater, control, and motor, looks like I'd be at 11.25A.
Assuming the motor is .25.
Not sure which would be best..... running at 1.25A over the breaker, if it doesn't trip, or bumping the breaker to 15A, which is 3.75A over the equipment.

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Fenrir

· #20 · Apr 30, 2012

Just remember you usually only get one chance to screw up this kind of thing. Be safe!

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