Range plug to 2-120V outlets

[madpenguin]

Here. A picture is worth a thousand words as they say (and it only took me 30 minutes to do, not 45)

Look what now happens to the circuit. It's a straight up 240v run without the neutral. Receptacles 1 and 2 are now in series with one another instead of being in parallel.

 

[madpenguin]

And here is a picture of a properly wired and working MWBC.

 

[madpenguin]

And I'll also say that the OP using these fuses is kinda sketchy. There is no common trip/blow on that thing. Atleast I don't think they will blow at the same time if one leg overloads. Sure doesn't look like it.

Also, when using MWBC's, each hot leg HAS to originate from opposite phases or legs in the panel. This is one reason why you use a double pole breaker. To insure your drawing power from both hot legs in the panel.

If you were to use single pole breakers for a MWBC and each breaker was stabbed onto the same hot leg/buss, then both loads would not cancel each other out, and in the above diagram, the neutral would be seeing 18A worth of current, not 2 amps.

MWBC's have many benefits such as reduced voltage drop and reduced load on the neutral, but only if you wire them correctly. If you don't know what your doing and make a mistake, it will be a costly one for sure. You can either destroy 120v equipment or burn your house down.

I still like to use them, but with the introduction of 08's beefed up code, MWBC's are going the way of the dinosaur, atleast in residential applications....

 

[dotblunt]

And I'll also say that the OP using these fuses is kinda sketchy. There is no common trip/blow on that thing. Atleast I don't think they will blow at the same time if one leg overloads. Sure doesn't look like it.

Alright, what do you suggest as a simple cost effective means of preventing only one leg from blowing, or of protecting the other should that happen? Edit2-I've done some research, I don't think what I'm planning is safe...I think my edit below is the way to go, opinions?

I'll be running only 1-1000W Core and Coil ballast per leg, nothing more.


DB

EDIT- (Just a thought) I'll be wiring the ballast myself...can I safely wire the 2 of them 240V (that is, run the both off a single 240V outlet) and avoid the split? Damn, then I need a 240V timer... Ok, only $60 for a good 240V 40Amp intermatic timer...thats not bad so long as I can run the 2 ballasts and the surge voltage isn't too great.

 

[dotblunt]

Alright, how about this: 25' 240V wire to my room, into the 240V intermatic 40AMP timer, out the other end then pigtailed to the 2 ballasts wired 240V? Of course, using 2-20AMP fuses rather than the 40s.

Safer? Seems it, also simpler...if a few more dollars.

I don't want this even remotely sketchy, if i get caught I want this 100% defensible.

DB

 

[PharmaCan]

Alright, how about this: 25' 240V wire to my room, into the 240V intermatic 40AMP timer, out the other end then pigtailed to the 2 ballasts wired 240V? Of course, using 2-20AMP fuses rather than the 40s.

Safer? Seems it, also simpler...if a few more dollars.

I don't want this even remotely sketchy, if i get caught I want this 100% defensible.

DB

If you want to be 100% sure that you will trip both lines simultaneously, just get a simple disconnect box & breakers and put it between the receptacle and the ballasts.

PC

 

[dotblunt]

Alrighty, my whole point to this was to minimize the disruption to my other circuits but after thoughtful consideration I've decided to say the hell with this.

I'll sacrifice 2 of my 15 Amp 120V circuits and run a 1000Wer off each, blocking off the remaining plugs with those baby safety things.

Thank you all, K+

DB

 

[madpenguin]

Alright, what do you suggest as a simple cost effective means of preventing only one leg from blowing, or of protecting the other should that happen? Edit2-I've done some research, I don't think what I'm planning is safe...I think my edit below is the way to go, opinions?

I'll be running only 1-1000W Core and Coil ballast per leg, nothing more.


DB

EDIT- (Just a thought) I'll be wiring the ballast myself...can I safely wire the 2 of them 240V (that is, run the both off a single 240V outlet) and avoid the split? Damn, then I need a 240V timer... Ok, only $60 for a good 240V 40Amp intermatic timer...thats not bad so long as I can run the 2 ballasts and the surge voltage isn't too great.

Look, if only one fuse blows then you still have one working 120v receptacle. Seeing as how the fuse plate is one piece, when ever you pull it out, your killing both hot legs which qualifies as a proper disconnecting means of killing both L1 and L2.

I don't know why I said it was sketchy. No biggie. If only one fuse blows then that particular circuit can't be complete. There will be no amp draw from that leg so nothing to go back down the neutral. Therefore, your just left with one working 120v receptacle.

Now.... I've seen fuses only partially blow before. That's not supposed to happen but I know for a fact that it can and occasionally does. In that case, one of your 120v receptacles might only be seeing 54v instead of 120v. That could really fuck motor and inductive loads. But again, that's fairly rare as far as I'm aware.

This is why fuses just basically suck. Go with your original plan if you want just make sure you have absorbed all I've said about MWBC's....


On a different note, I almost blew myself up today PC. Disco exploded in my face and burnt a little of my hair. Really bad day at work and I was thinking it might be nice to have a thank you for all the time it took me to answer your question.:wink: No suck luck. But that's o.k.... I still love ya'.

 

[dotblunt]

On a different note, I almost blew myself up today PC. Disco exploded in my face and burnt a little of my hair. Really bad day at work and I was thinking it might be nice to have a thank you for all the time it took me to answer your question.:wink: No suck luck. But that's o.k.... I still love ya'.

How much Karma do you want? Good lord, didn't I rep you twice this thread alone?

DB

 

[madpenguin]

I don't think icmag karma counts for much TBH... :smile:

It was just a moronic mistake on my part for not focusing on where hot and ground were in relation to one another.

I hate to say this seeing as how the POCO doesn't like it, but usually it's just best to pull the meter face and be done with it (when that's the only way to kill what you are working on). Wouldn't have happened had I done that (that or keep my mind on my work).

You guys really need to be carefull when your working on live stuff. In fact, there is NO reason for anyone to work on live equipment. What's that saying?

"There are no old/bold electricians"...

 

[PharmaCan]

On a different note, I almost blew myself up today PC. Disco exploded in my face and burnt a little of my hair. Really bad day at work and I was thinking it might be nice to have a thank you for all the time it took me to answer your question.:wink: No suck luck. But that's o.k.... I still love ya'.

Actually, I was going to take my meter and put it on the disconnected neutral side of a receptacle with a 1000w ballast turned on and see how much power was coming out of the neutral to see if your theory was valid. Obviously it would work if the receptacle hand a jumper between the hot and neutral contacts, but I'm skeptical about 120 volts coming out of an appliance. (Then there's always the fact that experience dictates that the wire connections most likely to come loose in the no-pigtails scenario are the ones making the jumper between the two receptacles, not the incoming neutral wire, since it is the jumper that twists when working on the receptacle/installation.) In the circumstances you described I'm pretty sure you're going to have a situation that just knocks both breakers off.

Sorry to hear about your accident. The burns hurt a lot more than the jolts, most of the time. If I have to do any work on a panel, I always call the PowCo and ask them to take the locking ring off. They're always happy to do it. (SoCal Edison is anyway. Up in Washington state they get cantankerous about anyone but PowCo employees removing/replacing the meter. One OPALCO guy actually tried to tell me that the meter could explode unless an OPALCO employee put it in. I guess they have magic hands or something???) If I have to work on a hot panel, I often use rubber gloves and always use screwdrivers where I've put tubing covering everything but the tip.

The dumbest thing I ever did working with hot wires was to leave two hots, on different phases, sticking out of a couple of receptacles that were kind of close to each other. I was thinking of & working on something else when I walked up to the wall and just happened to bump into the wires, one with each hand. I couldn't move! I was standing there frozen by the electricity thinking "Man, this is a dumb fucking way to die." I finally managed to get my legs to relax enough that I fell over and broke the connection, but I was stiff as a board and couldn't move at all while the electricity was going through me.

Stay safe - with any luck one day you'll be an old curmudgeon like me.

PC

 

[dotblunt]

Thank you madpenguin, PharmaCan and Fear for the solid advice!

And stay safe!

DB