Thread: 240 volt breakers

Today I had (2) 240 breakers with only one wire connected. This is not the first time I have seen this type of wiring, typically I see this at least twice month. If there was an overload, would both sides of the breaker trip?

Similar Threads:

• 120 volt dryer?
• 240 volt breaker
• 240 volt double pole breakers
• Does 2 x 120 volt = 240 volt wiring?
• 240-volt versus 208-volt

Originally Posted by Richard Roshak

Today I had (2) 240 breakers with only one wire connected. This is not the first time I have seen this type of wiring, typically I see this at least twice month. If there was an overload, would both sides of the breaker trip?

Yes.

240 volt breakers (double pole breakers) are (basically) the same as two individual breakers connected together internally.

When two separate breakers are put side by side for a 240 circuit, a handle tie is required to connect the two handles together so that if one side trips, the other side trips.

Double pole breakers are tied together inside instead of outside.

The only things about using a 240 volt breaker for a 120 volt circuit are: a) waste of space in the panel as you lose one breaker space to the unused half of the breaker; b) waste of money because double pole breakers cost more than single pole breakers.

Originally Posted by Jerry Peck

When two separate breakers are put side by side for a 240 circuit, a handle tie is required to connect the two handles together so that if one side trips, the other side trips.

This is INCORRECT. A handle tie is illegal and a safety hazard for converting two single pole breakers into a double pole. A handle tie only provides a common means of disconnect, not a common trip. It's generally only used for a multi-wire branch circuit (i.e., two legs that share a common neutral).

It's NOT illegal as long as both of the breakers are slash rated 120/240 volts and the tie handle is the right one for the style of breaker.

I don't buy the argument that was made about it being illegal. If for safety reasons you need a common means of disconnect, why wouldn't you want it to work when one of the circuits overloads?

Originally Posted by Jason V. Advani

This is INCORRECT. A handle tie is illegal and a safety hazard for converting two single pole breakers into a double pole. A handle tie only provides a common means of disconnect, not a common trip. It's generally only used for a multi-wire branch circuit (i.e., two legs that share a common neutral).

Originally Posted by Jerry Peck

Yes.


The only things about using a 240 volt breaker for a 120 volt circuit are: a) waste of space in the panel as you lose one breaker space to the unused half of the breaker; b) waste of money because double pole breakers cost more than single pole breakers.

There is no automatic loss of space, as you can use a double-pole breaker to control two independent circuits. Not a wonderful idea, not terrible IMO, but I believe not illegal so long as circuit labeling is accurate. For instance, in my old house each room had a 20amp 120VAC circuit serving lights and receptacles. I combined two rooms, and if their circuits both originated from a 2-pole CB, no super inconvenience.

As for waste of money, sub specie aeternitatis that's true, but if the installer has a 2-pole in his truck and is out of single-poles, or if a 2-pole circuit has been removed with its CB left in the panel, it may be the more cost-effective way to go.

Originally Posted by Frank Norman

It's NOT illegal as long as both of the breakers are slash rated 120/240 volts and the tie handle is the right one for the style of breaker.

I don't buy the argument that was made about it being illegal. If for safety reasons you need a common means of disconnect, why wouldn't you want it to work when one of the circuits overloads?

I’m sorry, I should have been more clear. It’s not illegal in the sense that the police are going to come and arrest you. It’s a code violation and a safety hazard.

The “slash rating” is the voltage from phase (leg) to phase (leg) and from phase (leg) to ground. That has nothing to do with this application.

When you have a single phase 240VAC application with a factory-made two-pole breaker, you have a connection made to each leg and you need a common trip. When an overload condition exists on either or both legs, both legs need to disconnect. Nothing would prevent this equipment from having a neutral (grounded) connection such as in the case of a multiwire branch circuit or two 120VAC loads. In this case, you also have a common disconnect—you cannot shut off one leg without the other—that’s just how it comes.

When you use a field-installed tie handle, you do not necessarily have a common trip. Some breakers will, but it’s not guaranteed. Usually when you buy a two pole breaker that looks like it has a tie handle factory installed, but it’s non-removable and it’s also internally connected such that you get that common trip. They’re not the same thing. The only application where a tie handle is appropriate (that I’m aware of) would be a multiwire branch circuit. In this case you’re sharing a neutral across two phases (legs) and the neutral is typically sized for the full load (same size as the phase conductor). There’s absolutely no reason why you need the other phase (leg) to trip if you have an overload on one. You need the common disconnect, which is what the tie handle provides, because if you work on the circuit you need to remove power to everything as you’re sharing the neutral (and often times this is all in the same box). If you don’t have the common trip and you have a fault on one leg and the other leg stays connected, you’re asking for trouble—especially in a single phase 240V application.

I will challenge you to find written documentation from a manufacturer stating that you can use tie handle on two single pole breakers to create a two pole breaker for a single phase 240V load. I’ve been all over this issue in years past. I’m an EE with a PE (not that it really matters).

Originally Posted by david shapiro

There is no automatic loss of space, as you can use a double-pole breaker to control two independent circuits.

The original post said one 120 volt circuit from a double pole breaker - not two circuits from it.

[QUOTE=Jerry Peck;274769]The original post said one 120 volt circuit from a double pole breaker

Yes, I know. It's allowed. I'm referring to this:

Originally Posted by Jerry Peck

When two separate breakers are put side by side for a 240 circuit, a handle tie is required to connect the two handles together so that if one side trips, the other side trips

That's not allowed.

Jason,

David and I were discussing a different question ... on a different page, so to speak, from that.

My apologies that what I said did not reflect manufacturers advice and the current NEC code, a legal requirement in many jurisdictions. As you said, and per NEC2011, the code does not allow single-pole circuit breakers with identified handle ties to be used for the protection of ungrounded conductors for line-to-line connected loads.

I now realise that my posting was based on memory of NEC2005 which said "In grounded systems, individual single-pole circuit breakers with identified handle ties shall be permitted as the protection for each ungrounded conductor for line-to-line connected loads for single phase circuits or 3-wire direct-current circuits" (as well as for each ungrounded conductor of multi-wire branch circuits that serve only single-phase line-to-neutral loads).

I believe that whether a particular arrangement is illegal or not depends on which version of the code was in force when the installation was made. Presumably the code change was done in the name of safety but I don't know how significant a hazard the ties really caused.

A supplier description near the top of a search result gives "Convert any 2 adjacent one-pole breakers to an independent trip double pole circuit breaker with the QO Circuit Breaker Handle Tie. The tie offers Ul and CSA listings for safety. This handle is suitable for QO circuit breakers rated 120/240 VAC". To minimize incorrect use this description needs an additional note to say that the handle ties must not be used to create a double breaker for a 240V heater, or any other 240V circuit.

A safety hazard that worries me more exists in homes in my neighborhood which were knob and tube then rewired years ago with copper NMD cable and with two to six kitchen counter 15A outlets. These are split-duplex outlets fed by two circuits, each with a double 15A breaker or tied 15A breakers, but no GFCI. Two double-pole 15A GFCI QO breakers from Lowe's Canada would add safety but will cost $618.24 with tax. Any other solutions other than rewiring to current code?

Originally Posted by Jason V. Advani

I’m sorry, I should have been more clear. It’s not illegal in the sense that the police are going to come and arrest you. It’s a code violation and a safety hazard.

The “slash rating” is the voltage from phase (leg) to phase (leg) and from phase (leg) to ground. That has nothing to do with this application.

When you have a single phase 240VAC application with a factory-made two-pole breaker, you have a connection made to each leg and you need a common trip. When an overload condition exists on either or both legs, both legs need to disconnect. Nothing would prevent this equipment from having a neutral (grounded) connection such as in the case of a multiwire branch circuit or two 120VAC loads. In this case, you also have a common disconnect—you cannot shut off one leg without the other—that’s just how it comes.

When you use a field-installed tie handle, you do not necessarily have a common trip. Some breakers will, but it’s not guaranteed. Usually when you buy a two pole breaker that looks like it has a tie handle factory installed, but it’s non-removable and it’s also internally connected such that you get that common trip. They’re not the same thing. The only application where a tie handle is appropriate (that I’m aware of) would be a multiwire branch circuit. In this case you’re sharing a neutral across two phases (legs) and the neutral is typically sized for the full load (same size as the phase conductor). There’s absolutely no reason why you need the other phase (leg) to trip if you have an overload on one. You need the common disconnect, which is what the tie handle provides, because if you work on the circuit you need to remove power to everything as you’re sharing the neutral (and often times this is all in the same box). If you don’t have the common trip and you have a fault on one leg and the other leg stays connected, you’re asking for trouble—especially in a single phase 240V application.

I will challenge you to find written documentation from a manufacturer stating that you can use tie handle on two single pole breakers to create a two pole breaker for a single phase 240V load. I’ve been all over this issue in years past. I’m an EE with a PE (not that it really matters).

Originally Posted by Frank Norman

My apologies that what I said did not reflect manufacturers advice and the current NEC code, a legal requirement in many jurisdictions. As you said, and per NEC2011, the code does not allow single-pole circuit breakers with identified handle ties to be used for the protection of ungrounded conductors for line-to-line connected loads.

I now realise that my posting was based on memory of NEC2005 which said "In grounded systems, individual single-pole circuit breakers with identified handle ties shall be permitted as the protection for each ungrounded conductor for line-to-line connected loads for single phase circuits or 3-wire direct-current circuits" (as well as for each ungrounded conductor of multi-wire branch circuits that serve only single-phase line-to-neutral loads).

I believe that whether a particular arrangement is illegal or not depends on which version of the code was in force when the installation was made. Presumably the code change was done in the name of safety but I don't know how significant a hazard the ties really caused.

A supplier description near the top of a search result gives "Convert any 2 adjacent one-pole breakers to an independent trip double pole circuit breaker with the QO Circuit Breaker Handle Tie. The tie offers Ul and CSA listings for safety. This handle is suitable for QO circuit breakers rated 120/240 VAC". To minimize incorrect use this description needs an additional note to say that the handle ties must not be used to create a double breaker for a 240V heater, or any other 240V circuit.

A safety hazard that worries me more exists in homes in my neighborhood which were knob and tube then rewired years ago with copper NMD cable and with two to six kitchen counter 15A outlets. These are split-duplex outlets fed by two circuits, each with a double 15A breaker or tied 15A breakers, but no GFCI. Two double-pole 15A GFCI QO breakers from Lowe's Canada would add safety but will cost $618.24 with tax. Any other solutions other than rewiring to current code?

I have written documention from Square D that verifies your statement.

Originally Posted by Frank Norman

I now realise that my posting was based on memory of NEC2005 which said "In grounded systems, individual single-pole circuit breakers with identified handle ties shall be permitted as the protection for each ungrounded conductor for line-to-line connected loads for single phase circuits or 3-wire direct-current circuits" (as well as for each ungrounded conductor of multi-wire branch circuits that serve only single-phase line-to-neutral loads).

I believe that whether a particular arrangement is illegal or not depends on which version of the code was in force when the installation was made. Presumably the code change was done in the name of safety but I don't know how significant a hazard the ties really caused.

Well, we both learned something new. I was not aware it was only a recent change. Thanks for the enlightenment! I think that it's a significant hazard because a tripped condition is supposed to be off, but if it's still partially connected one might be in for a shock (no pun intended).

If you went back to the change request for the code (I forget the official name for this), there is probably some commentary. It might tough to find because for the 2005 NEC, it would have been circa 2002/20003.

Originally Posted by Frank Norman

A supplier description near the top of a search result gives "Convert any 2 adjacent one-pole breakers to an independent trip double pole circuit breaker with the QO Circuit Breaker Handle Tie. The tie offers Ul and CSA listings for safety. This handle is suitable for QO circuit breakers rated 120/240 VAC". To minimize incorrect use this description needs an additional note to say that the handle ties must not be used to create a double breaker for a 240V heater, or any other 240V circuit.

Agreed. I'm curious though ... it might be UL listed, but is it compliant if the OEM doesn't recognize it? Probably not. Best to use only the manufacturer's tie handle, I'd think.

Originally Posted by Frank Norman

A safety hazard that worries me more exists in homes in my neighborhood which were knob and tube then rewired years ago with copper NMD cable and with two to six kitchen counter 15A outlets. These are split-duplex outlets fed by two circuits, each with a double 15A breaker or tied 15A breakers, but no GFCI. Two double-pole 15A GFCI QO breakers from Lowe's Canada would add safety but will cost $618.24 with tax. Any other solutions other than rewiring to current code?

So, my understanding is that you have a MWBC feeding the kitchen receptacles. I think that the easiest solution is what you've described, but its probably the most expensive. Alternatively, you could replace each receptacle with a GFCI receptacle and don't use the protected downstream line connection. Each one would be its own independent GFCI. Could probably alternate the line connection down every other receptacle. Thoughts?

Originally Posted by Jerry Peck

The original post said one 120 volt circuit from a double pole breaker - not two circuits from it.

Understood, Jerry. But that second space remains available, provided you run a circuit suitable for the same level of OC protection and don't mind its simultaneous disconnection in the usually rare instance of tripping. Of course, it can make the trip more inconvenient,and troubleshooting the trip a wee bit harder.

- - - Updated - - -

Originally Posted by Jerry Peck

The original post said one 120 volt circuit from a double pole breaker - not two circuits from it.

Acknowledged, Jerry.
I argue that the second space remains available, even without changing out that CB, provided you want to run a second circuit of the same rating, and don't mind the two being disconnected simultaneously.

Originally Posted by david shapiro

Acknowledged, Jerry.
I argue that the second space remains available, even without changing out that CB, provided you want to run a second circuit of the same rating, and don't mind the two being disconnected simultaneously.

Which, to me, makes it wasted as why would you want to lose too circuits when only one trips.

If you go to www.nfpa.org/70, select the edition you want to find out about, select Revision information, you can open it and scroll down till you find the proposals.

Originally Posted by Jason V. Advani

So, my understanding is that you have a MWBC feeding the kitchen receptacles. I think that the easiest solution is what you've described, but its probably the most expensive. Alternatively, you could replace each receptacle with a GFCI receptacle and don't use the protected downstream line connection. Each one would be its own independent GFCI. Could probably alternate the line connection down every other receptacle. Thoughts?

This is what I did with the split duplex receptacles at my kitchen counters. I now have five separate GFCI receptacles alternating between the two circuits. I don't actually remember if they shared a neutral or if I was just too lazy to figure out which receptacles were first in the chain to use the downstream protection. There were definitely rooms where I just threw a separate GFCI receptacle in each box rather than testing which was first in the chain and using the downstream protection.

Now I need to check for a shared neutral because the breakers for these two circuits are not tied and they are not even adjacent so they can be tied easily. If they share a neutral, I will ask an electrician to fix that because I'm not about to start moving breakers around in my panel. I'm optimistic that the absence of adjacent breakers is an indication that two cables with two neutrals were run, rather than an MWBC, but I have a vague memory that somewhere in my house I did run into an MWBC which caused me to use GFCI receptacles at every location.

Thanks as always for the information you guys share with each other and the rest of us.

Originally Posted by Jason V. Advani

..
So, my understanding is that you have a MWBC feeding the kitchen receptacles. I think that the easiest solution is what you've described, but its probably the most expensive. Alternatively, you could replace each receptacle with a GFCI receptacle and don't use the protected downstream line connection. Each one would be its own independent GFCI. Could probably alternate the line connection down every other receptacle. Thoughts?

This is a most useful suggestion and I see that others have done something similar. The user will just have to avoid using the 900W toaster and 1500W kettle at the same time on the same outlet. But then with the previous wiring they had to avoid using them at the same time if plugged into the same phase of the first and third outlets, or second and fourth etc.. Weird.

After more years on 110/220 60HZ and GFCI than on 240V 50Hz with ELCB, I still think the 240V ring main wiring is better.