trick question!

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davedottcom

davedottcom

Senior Member
Can you feed multiwire circuits from a "Tandem" 20-20 circuit breaker?

For instance, a 12/3 with the red wire on one terminal of the 20-20 tandem breaker and the black wire on the other terminal of the 20-20 tandem breaker, with both circuits sharing the white grounded conductor and the bare ground.

:cool:

Dave
 
Re: trick question!

Ok, I'll bite. it's late, I'm tired. I'll answer quickly, without much thought.

Only if you read 240 across the terminals. Some tandems pick up opposite phases.
 
Re: trick question!

Confused How does a tandem pick up 2 phases,all the tandems I have seen even zinsco`s use 1 breaker space ;)
 
Re: trick question!

"This answer I have to hear"

All (R38) style Sylvania tandem breakers use only 1 space, But only Some of them pick up BOTH phases.
:p

Dave
 
Re: trick question!

I suspect this is possible in more ways than one might expect.

In the current catalog, Siemens has a handle tie for the inner two handles of two single pole tandems that are side by side.

Take a look at the image in the upper left corner of the second page of this .pdf from the Speedfax catalog.

Also, Siemens sells a selection of tandem two pole non-common trip and common trip breakers as shown on this Speedfax page . Note that some of the outer pairs of ?" breakers have a factory installed wishbone handle tie, to help make them work.
 
Re: trick question!

Al, I meant on the same breaker...I guess I tricked myself!
But yea, you've got a point. I've seen it done on HOMELINE tandems, just like you described.

Dave
 
Re: trick question!

Ah, so.

I see so few Sylvania in my work area. . .

I have a few Zinsco breakers that have been rattling around in one of the really hard to get at bins in the truck. I don't think I've put one on a bus in better than 20 years.
 
Re: trick question!

Originally posted by al hildenbrand:

Also, Siemens sells a selection of tandem two pole non-common trip and common trip breakers
Click to expand...
Yea...well...they aren't Called "Tandem" breakers! They are called triplex and Quads! :p


"I have a few Zinsco breakers that have been rattling around in one of the really hard to get at bins in the truck."

Check them out sometime...some hit both phases and some don't. The ones that do are exactly like the 2-pole 20's (thins) but without the tie-bar.

Dave
 
Re: trick question!

As far as Siemens goes, the "tandem" is jargon. Siemens only sells duplex breakers, etc., not tandems. . . :D
 
Re: trick question!

Also note the smaller contact area on the tandem Zinsco breakers. Those more than the full size tend to the burn the bus up after awhile. They must have really been the 'bomb' up here in the Pacific NW during the 50's and 60's, cus about 75% of the houses from that era have them. I wonder why they lost their UL rating. :confused:
 
Re: trick question!

75% :eek:

Are they as expensive there as they are here? I pay from $40.00 - $60.00 for most.

$40.00 for used
$60.00 for new

Luckily I don't see too many of them.

Dave
 
Re: trick question!

Originally posted by davedottcom:
75% :eek:

Are they as expensive there as they are here? I pay from $40.00 - $60.00 for most.

$40.00 for used
$60.00 for new

Luckily I don't see too many of them.

Dave
Click to expand...
Yes...yes they are. You are talking $60.00 for a single pole 15 or 20, correct? I tell them they could get a whole new panel with breakers for the cost of a 2-pole 50 for that hot-tub, minus the labor, of course. I just did a change out Wednesday of an overhead, flushmount, meter/panel combo, weatherproof 100A Zinsco. UGH...what a nasty, dirty job. My sawzall got a workout that day.
 
Re: trick question!

Siemens has a quad circuit breaker that I have used to feed TWO 3-wire circuits.
 
Re: trick question!

"Wafer". That's a new one for me.

Wafer breaker.

I like it.
 
Re: trick question!

Originally posted by jimwalker:
Tandem breakers are inviting problems.Would only use them if it is the last choice before adding a panel
Click to expand...
I wouldn't really say that you're really inviting problems performance wise, but I feel that using them in a new installation is not quality work. Many times I have seen a new panel that's filled to the hilt with peanut breakers and no room for expansion. I guess that's the problem with going with the low bidder...you get what you pay for.
 
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