WHEN I NEED TO BREAK THE NEUTRAL OF AN AC DISCONNECT SWITCH?
- Thread starter mustafa
- Start date
- Status
- Location
- New Jersey
- Occupation
- Journeyman Electrician
The only place I know of that it's required is in the service disconnect. {230.75}
Please turn off the CAP lock.
Please turn off the CAP lock.
- Location
- Massachusetts
And it can be a sperate link, it does not have to happen when you open the service disconnect.
On the other hand the power supply to fuel dispensers is required to break the neutral with the hots.
kwired
Electron manager
- Location
- NE Nebraska
- Occupation
- EC
For most applications there is no requirement to break the neutral with the disconnect switch. If you do break it, it must be simultaneously or after the ungrounded conductors are opened, as well as simultaneous or first make when closing the switch.
kwired
Electron manager
- Location
- NE Nebraska
- Occupation
- EC
You are not required to break the neutral with the disconnect. If you do, it must open simultaneously with the ungrounded conductors.
Most units like you are describing will not have a neutral, in North America anyway.
jumper
Senior Member
- Location
- 3 Hr 2 Min from Winged Horses
On phone, do not have NEC handy.
My feeble brain vaguely remembered something about motors and breaking the noodle.
Do not recall if the section was about a situation where it was required or permitted.
Anyone got a NEC close? Somewhere in 430.
This was something besides a fuel dispenser I think or maybe not.
My feeble brain vaguely remembered something about motors and breaking the noodle.
Do not recall if the section was about a situation where it was required or permitted.
Anyone got a NEC close? Somewhere in 430.
This was something besides a fuel dispenser I think or maybe not.
kwired
Electron manager
- Location
- NE Nebraska
- Occupation
- EC
400/230 volt Y system?
If so does NEC apply? NEC wouldn't require breaking the neutral but such a system is not normally in areas where NEC does apply, I think.
Even though the system is not specifically mentioned the NFPA is an "International Codes and Standards Organization" which is the reason some things are mentioned in the NEC that are not used in most areas.
For example, I don't think flammable anesthetics are used in US hospitals however they are in some other countries which is the reason they are still mentioned in article 517.
Roger
kwired
Electron manager
- Location
- NE Nebraska
- Occupation
- EC
NFPA wants to be international, they are not everywhere though.
Try to comply with 210.52 and a few other places where 15/20 amp 120 volt outlets are requried when you don't even have 120 volts present in your supply system
Look at the cover of your code book. That doesn't mean it's adopted by every country but it is used as a guide by many.
Roger
what is the technical explanation behind breaking neutral feeding dispensers?
- Location
- Placerville, CA, USA
- Occupation
- Retired PV System Designer
Not sure if it is "the" reason, but if the POCO or feeder neutral is compromised, then the neutral wire could end up at a potential above ground. By opening the neutral too you can be more assured that no electrical energy is entering the dispenser.
You may use a 4 pole disconnect switch in addition to any surge protector to switch off any vulnerable equipment to be protected from severe surges during a thunderstorm.
I have found this in Siemens safety switch catalouge
4 & 6 pole switches are commonly used
as a disconnecting means for two-
speed, two-winding motors. Fused
switches provide both over current and
short-circuit protection. Non-fusible
switches normally provide a local
disconnection means for two-speed
motors, which are remote from their
motor controller. 4 pole switches are
also used in 3-phase, 4-wire circuits
when a switching neutral is required.
All 4 & 6 pole switches are service
entrance rated
- Location
- Massachusetts
Explain this surge.
First, what is the difference between a switch and a disconnect switch?
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