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Old 08-16-2019, 12:23 AM   #1
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2 circuits on one wire


Hello...

I have a 10/3 wire no ground running to a 220v outlet. I have 4 of these total each running to a room each under a window. This house currently has no heat or ac. I dont want to use ptac or mini splits.

I have several questions.

Can I use a 20 amp single pole double circuit (tandem) breaker for this outlet? My square d main panel supports tandem. The breaker says 120/240 on it.

I want to run a 220v wall mounted heater on this circuit. I also want to run a 110v window ac unit on this
Same circuit.

1)Purchase square d panel 30 amp main lug 2 spaces 2 circuits with feed through lugs. Put 20 amp breaker 110v for window ac using gfci outlet since there is no ground. Use feed through lugs for the 220v wall mounted heater still protected by 20 amp x 2 tandem breaker in main panel?

2)Going to ask the obvious here too, but it is probably a no no. Could i just wire the 110v gfci outlet to one of the hots from the 220v outlet, and the neutral. The 220v heater and 110v ac would never be on at the same time?

Thanks
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Old 08-16-2019, 08:42 AM   #2
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As to (2), yes. Be sure to feed with a 2 pole breaker so both hots are switched together and use a 120 volt GFCI
Receptacle.
As to (1), I have never seen a 2 circuit panel with feed thru lugs. Do you mean back feeding a 2 pole breaker to feed the panel? Are you using 2 separate cables from this panel?
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Old 08-16-2019, 05:50 PM   #3
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Re: 2 circuits on one wire


Quote:
Originally Posted by slipparee View Post
Hello...

I have a 10/3 wire no ground running to a 220v outlet. I have 4 of these total each running to a room each under a window. This house currently has no heat or ac. I dont want to use ptac or mini splits.

I have several questions.

Can I use a 20 amp single pole double circuit (tandem) breaker for this outlet? My square d main panel supports tandem. The breaker says 120/240 on it.

A tandem breaker does not have 240V across the two outputs, it just has the same 120V. You need actual 2-pole breakers to get to 240V


Quote:
Originally Posted by slipparee View Post
I want to run a 220v wall mounted heater on this circuit. I also want to run a 110v window ac unit on this
Same circuit.

1)Purchase square d panel 30 amp main lug 2 spaces 2 circuits with feed through lugs. Put 20 amp breaker 110v for window ac using gfci outlet since there is no ground. Use feed through lugs for the 220v wall mounted heater still protected by 20 amp x 2 tandem breaker in main panel?

You cannot set a panel without grounding it. An EGC will be required. Note that NEC allows you to run a separate EGC however you want, so you don't have to follow the original wiring.



Link to the panel you're describing? You can usually just get a feed-thru kit that mounts in the breaker space.


Quote:
Originally Posted by slipparee View Post
2)Going to ask the obvious here too, but it is probably a no no. Could i just wire the 110v gfci outlet to one of the hots from the 220v outlet, and the neutral. The 220v heater and 110v ac would never be on at the same time?

Thanks

While it would work technically, I don't know the exact NEC ruling off the top of my head.





The easier solution is to re-purpose the wiring for 120V 2W+GND and just run a 120V heater.
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Old 08-16-2019, 06:39 PM   #4
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Re: 2 circuits on one wire


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Originally Posted by keep_hope_alive View Post
A tandem breaker does not have 240V across the two outputs, it just has the same 120V. You need actual 2-pole breakers to get to 240V





You cannot set a panel without grounding it. An EGC will be required. Note that NEC allows you to run a separate EGC however you want, so you don't have to follow the original wiring.



Link to the panel you're describing? You can usually just get a feed-thru kit that mounts in the breaker space.





While it would work technically, I don't know the exact NEC ruling off the top of my head.





The easier solution is to re-purpose the wiring for 120V 2W+GND and just run a 120V heater.
The OP does not mention the panel brand but GE makes a 1" breaker that bridges 2 stabs and provides 240.

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Old 08-16-2019, 11:31 PM   #5
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I plan on grounding the panel next week. It had a 100 amp fuse panel which i replaced with 100 amp square d homeline 20 spaces 40 cirxuits. The only thing grounded is the circuit i ran under the panel for my router to plug in. My hot water tank will be grounded. My dryer too. I put in new wiring for those.

I am going to add a 200 amp outdoor main while i start the process of going to 400 amp service. I didnt ground anything yet because i need a seperate grounding bar kit for the few grounds i will have for this 100 amp main. I jusr wanted power on.

So by taking red and black in the same 20 amp tandem i am not getting 240v?

But it is 120v x 2?

Ok if so... I would need to take 120v from 2 tandem breakers?

Red Red in 1 tandem. Black Black in another right above or below the tandem with Red Red?

Repeat this x 2 for all four of my 220v circuits heat/air.

And i suppose hunting for the handle tie will be fun but i assume they are out there.

My panel has 2 spaces left after everything is finished and i was going to use those.
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Old 08-17-2019, 12:01 AM   #6
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Re: 2 circuits on one wire


Quote:
Originally Posted by slipparee View Post
I plan on grounding the panel next week. It had a 100 amp fuse panel which i replaced with 100 amp square d homeline 20 spaces 40 cirxuits. The only thing grounded is the circuit i ran under the panel for my router to plug in. My hot water tank will be grounded. My dryer too. I put in new wiring for those.

I am going to add a 200 amp outdoor main while i start the process of going to 400 amp service. I didnt ground anything yet because i need a seperate grounding bar kit for the few grounds i will have for this 100 amp main. I jusr wanted power on.

So by taking red and black in the same 20 amp tandem i am not getting 240v?

But it is 120v x 2?

Ok if so... I would need to take 120v from 2 tandem breakers?

Red Red in 1 tandem. Black Black in another right above or below the tandem with Red Red?

Repeat this x 2 for all four of my 220v circuits heat/air.

And i suppose hunting for the handle tie will be fun but i assume they are out there.

My panel has 2 spaces left after everything is finished and i was going to use those.

Consider that each breaker space is on a single pole. You have to span two poles to get 240V. A tandem just adds two breakers on the same single pole.



You can buy a dual 20A 2-pole tandem for some panel MFRs
https://www.homedepot.com/p/Eaton-BR...0220/100167402
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Old 08-17-2019, 12:08 AM   #7
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I umderstand now.

Here is the other part so i can seperate the 220v outlet and also run a 110v without having to fish wire.

https://www.lowes.com/pd/Square-D-2-...Center/3457972
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Old 08-17-2019, 08:58 AM   #8
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Re: 2 circuits on one wire


As long as the breaker in the panel is a 2 pole 20 amp you can classify the circuit as a MWBC (Multi wire branch circuit) per NEC 210.4. Normally you can only use a MWBC for line to neutral loads but exception C1 would seem to a allow a line to line load.

What this means is: use the 10/3 from the 20 amp 2 pole and supply your 240 volt load and branch off to a 120 volt receptacle. Remember 20 amps only and the danger is if the 240 device is drawing power at the same time as the 120 volt circuit you could exceed 20 amps and trip the breaker.
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Old 08-17-2019, 01:56 PM   #9
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Re: 2 circuits on one wire


You are permitted to replace an ungrounded 120v receptacle with a GFCI, and to replace ungrounded downstream 2-prong receptacles with 3 prong if labeled "GFCI protected, not grounded."



You are not permitted to install a new receptacle that is not grounded, GFCI or otherwise. So your existing ungrounded 30a 240 receptacles are grandfathered, replacing them with 20a ungrounded and downsizing the breakers is a grey area, but splitting off a new 120v circuit from an already long non-compliant circuit is not permitted.
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Old 08-17-2019, 02:02 PM   #10
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Re: 2 circuits on one wire


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Originally Posted by LawnGuyLandSparky View Post
You are permitted to replace an ungrounded 120v receptacle with a GFCI, and to replace ungrounded downstream 2-prong receptacles with 3 prong if labeled "GFCI protected, not grounded."



You are not permitted to install a new receptacle that is not grounded, GFCI or otherwise. So your existing ungrounded 30a 240 receptacles are grandfathered, replacing them with 20a ungrounded and downsizing the breakers is a grey area, but splitting off a new 120v circuit from an already long non-compliant circuit is not permitted.
+!, I had to go back and read the first post. Since the 3 wire cable is ungrounded, it is unusable for you plan. Rerun new cable.
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Old 08-24-2019, 11:56 PM   #11
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I have decided to just run 220v outlets with this. There are now 4 total 220v outlets. I used tandem 20 amp breakers. The existing wire is 10/3 with no ground.

The picture may help. Starting with the bottom 20 amp tandem above the 100 amp main as the box was mounted inverted here is how i have it wired.

The very bottom half of the breaker is hooked to a 110v outlet that is on its own circuit.

Moving up... I have one hot for 220v. The next tandem breaker at the bottom has the other half of this same 220v circuit. Then the top of the same tandem has one hot for the next 220v cirxuit. Then the bottom of next tandem has the othet hot of the same 220v circuit. Etc. Continuing until i have 4 seperate 220v circuits.

Can i put a handle tie on each of these 4 220v circuits as there is a hole for one in the spots i have these setup and be OK here?
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Old 08-25-2019, 12:10 AM   #12
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Maybe this picture will help better.
All of the ON breakers are 220v.

I need to place handle ties between each tandem breaker.

Correct?
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Old 08-25-2019, 12:29 AM   #13
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One more queation plz?

OK... Now all of that is sorted i hope... i have another question about this same circuit.

These are all inside of a 100amp main panel. I am going to upgrade the meter socket to a 200 amp combo panel with a 200 amp main breaker. That would make this 100 amp panel no longer the first point of disconnect. So i need to seperate the neutrals and grounds which i have aldeady done by adding a ground bar inside this 100 amp panel( I also ran a ground outside from this 100 amp panel to the ground rod outside the house where the meter socket is grounded) I did put a short ground wire over to a neutral spot in the 100 amp panel temporarily since i have not yet installed the upgraded meter socket yet.

And yes finally here is my question. And thanks for reading all that...

I want these 220v outlets to be grounded yes correct? So i want to run there third wire not black or red over to the ground bar i installed in this 100 amp panel?

Whenever i get the new meter socket combo panel installed simply remove the temporary ground wire running from the ground bar to neutral screw, and remove the green bonding screw. Then good to go?
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Old 08-25-2019, 07:00 AM   #14
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Re: 2 circuits on one wire


Quote:
I need to place handle ties between each tandem breaker.

Correct?
Correct. Which means you will have all 5/10 tandem breakers tied together since you can't cut the tie on the tandem. One trip should trip all 10 circuits.
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