Single Pole VS Double Pole Circuit Breaker

Status
Not open for further replies.

iwire

Moderator
Staff member
Location
Massachusetts
Smart $:
If there is already a GFCI upstream, single pole breaker instead of two pole breaker for an ungrounded 460V two wire system may be used. It results not only in safer operation but also may lower cost (single pole instead two pole breaker).
What do you think from the point of view of CMP?
:)

There is no such thing as a GFCI for 460 volts or for ungrounded systems.
 

Haji

Banned
Location
India
You can use a breaker in conjunction with it to make the combination act as GFCI or at least an alarm to wake you up. But it is just a code proposal, my friends!
 

kwired

Electron manager
Location
NE Nebraska
There is no such thing as a GFCI for 460 volts or for ungrounded systems.
I wouldn't necessarily make that claim, but it definitely is not something in high enough production levels that it would cost less then a two pole breaker that is more common to see in higher production levels - which is what the original application was about for this - at least in North American markets.
 

iwire

Moderator
Staff member
Location
Massachusetts
I wouldn't necessarily make that claim, but it definitely is not something in high enough production levels that it would cost less then a two pole breaker that is more common to see in higher production levels - which is what the original application was about for this - at least in North American markets.

I will maintain that claim in any area under the NEC.

GFCI has a very specific meaning and is not to be confused with GFP or ground fault detection.
 

kwired

Electron manager
Location
NE Nebraska
I will maintain that claim in any area under the NEC.

GFCI has a very specific meaning and is not to be confused with GFP or ground fault detection.
I can agree with that, and that Haji maybe should have called it GFP, my main intention was to mention that it likely would not cost less then using a typical 2 pole breaker, without even looking at exactly what he had or considering any other issues it may have for this application.
 

Smart $

Esteemed Member
Location
Ohio
Smart $:
If there is already a GFCI upstream, single pole breaker instead of two pole breaker for an ungrounded 460V two wire system may be used. It results not only in safer operation but also may lower cost (single pole instead two pole breaker).
What do you think from the point of view of CMP?
:)
A little late to this topic branch, as you can see, but the two single pole vs one double pole relates back to the requirement for independent or common trip.

Where required to be common trip, there is no choice in the matter... and common trip definitely cost more than independent trip.

On the other hand, an independent-trip double pole costs just a bit more than two single pole breakers plus handle tie. Typically an independent-trip double pole is just two single pole breakers factory riveted together and factory-installed handle tie. Some may cost a bit more than 2x due to market demand vs. supply considerations made by the manufacturer and distribution chain.

Given other replies to your post, there's no need for me to add any comment on the GFCI portion... :)
 

kwired

Electron manager
Location
NE Nebraska
A little late to this topic branch, as you can see, but the two single pole vs one double pole relates back to the requirement for independent or common trip.

Where required to be common trip, there is no choice in the matter... and common trip definitely cost more than independent trip.

On the other hand, an independent-trip double pole costs just a bit more than two single pole breakers plus handle tie. Typically an independent-trip double pole is just two single pole breakers factory riveted together and factory-installed handle tie. Some may cost a bit more than 2x due to market demand vs. supply considerations made by the manufacturer and distribution chain.

Given other replies to your post, there's no need for me to add any comment on the GFCI portion... :)

Cost may somewhat depend on what brand/line and what trip setting is and taking in consideration what production quantities are. Single pole breakers in general are produced in much higher quantities in 15-30 amp setting especially for 120 volt series. Go above 30 amps and two and three pole breakers possibly cost less then if you were to find single pole in same series and use handle ties where it would be permissible just because they normally don't make/sell many of those in single pole units.
 

Haji

Banned
Location
India
Given other replies to your post, there's no need for me to add any comment on the GFCI portion... :)
The replies including yours did not deal with the viability of my suggested code proposal for ground fault detection and a breaker/alarm combination for an ungrounded system in context with the usage of single pole breaker.:roll:
 

Smart $

Esteemed Member
Location
Ohio
Cost may somewhat depend on what brand/line and what trip setting is and taking in consideration what production quantities are. Single pole breakers in general are produced in much higher quantities in 15-30 amp setting especially for 120 volt series. Go above 30 amps and two and three pole breakers possibly cost less then if you were to find single pole in same series and use handle ties where it would be permissible just because they normally don't make/sell many of those in single pole units.
Good point. Must have been thinking too small when I posted. :D
 

Smart $

Esteemed Member
Location
Ohio
The replies including yours did not deal with the viability of my suggested code proposal for ground fault detection and a breaker/alarm combination for an ungrounded system in context with the usage of single pole breaker.:roll:
If I were a CMP member considering your proposal, I would reject it on the basis of inadequate substantiation. This happens quite often to good proposals that simply lack substantiation, or substantiate with abstract and/or vague notions.
 

iwire

Moderator
Staff member
Location
Massachusetts
The replies including yours did not deal with the viability of my suggested code proposal for ground fault detection and a breaker/alarm combination for an ungrounded system in context with the usage of single pole breaker.:roll:

How would your device be supplied by a single pole breaker?

Where do I connect the second supply line too?

I think your idea falls flat.
 
Status
Not open for further replies.
Top