480Volt GFCI

[wireday]

210.8B 3 phase GFCI 150volts or less to ground, So with 480 its business as usual? Do they even make 3 pole 480volt GFCI protection?

 

[infinity]

In a 480/277 Wye system phase to ground voltage is 277 volts.

 

[wireday]

I know its not required, just curious if it was available.

 

[hillbilly1]

Gfep for heat tape.

 

[ptonsparky]

They make all sorts of different GF sensors with selectable trip points. Suitable for use as a class A GFCI? I would venture a guess as not a snowballs chance in...well you get the idea.

 

[wireday]

They make all sorts of different GF sensors with selectable trip points. Suitable for use as a class A GFCI? I would venture a guess as not a snowballs chance in...well you get the idea.

Can you show a link? Thanks

 

[winnie]

SB6000 - Littelfuse

m.littelfuse.com

 

[ptonsparky]

Can you show a link? Thanks

https://cdn.automationdirect.com/static/specs/acuampgfs.pdf

I'm sure there are others.

 

[Jraef]

Understand that the term “GFCI” is SPECIFIC to personnel protection with a 6 mA trip threshold, referred to as Class A protection. The intent is to protect people where they are plugging things in and out of receptacles, or are in and around water, like baths, sinks, pools or outdoors.

480V is an industrial/commercial voltage primarily for large machinery where ostensibly there will be standards for how it is used and who has access to it. It’s a safe bet that most 480V equipment will not stay energized with that level of sensitivity. “Ground Fault” protection for 480V equipment, when required, is going to be EQUIPMENT level protection denoted as “GFEP,” not GFCI personnel protection.

 

[wireday]

Understand that the term “GFCI” is SPECIFIC to personnel protection with a 6 mA trip threshold, referred to as Class A protection. The intent is to protect people where they are plugging things in and out of receptacles, or are in and around water, like baths, sinks, pools or outdoors.

480V is an industrial/commercial voltage primarily for large machinery where ostensibly there will be standards for how it is used and who has access to it. It’s a safe bet that most 480V equipment will not stay energized with that level of sensitivity. “Ground Fault” protection for 480V equipment, when required, is going to be EQUIPMENT level protection denoted as “GFEP,” not GFCI personnel protection.

Are you saying just do it,

 

[winnie]

I will partially disagree with Jraef.

As used by UL, 'GFCI' applies to any residual current device that is intended to protect people.

For high voltage and industrial applications UL recognizes the need for higher trip thresholds, and describes different classes of GFCI offering different protection for different circumstances.

The physics that Jraef describes is spot on. A 50A 480V piece of apparatus is very likely to have higher necessary leakage than a toaster, and class A protection impossible to use.

See https://iaeimagazine.org/features/n...have-a-proactive-option-for-shock-protection/

Jon

 

[kwired]

I know its not required, just curious if it was available.

Shhh. don't give them any ideas for future codes.

Understand that the term “GFCI” is SPECIFIC to personnel protection with a 6 mA trip threshold, referred to as Class A protection. The intent is to protect people where they are plugging things in and out of receptacles, or are in and around water, like baths, sinks, pools or outdoors.

480V is an industrial/commercial voltage primarily for large machinery where ostensibly there will be standards for how it is used and who has access to it. It’s a safe bet that most 480V equipment will not stay energized with that level of sensitivity. “Ground Fault” protection for 480V equipment, when required, is going to be EQUIPMENT level protection denoted as “GFEP,” not GFCI personnel protection.

Unless maybe you looking at this from job security prospective.

AFCI's already leaving the contractor bearing the brunt of the cost of maintaining these things. Material cost not being a major factor but rather all the non reimbursed time spent troubleshooting most the problems associated with them.

 

[paulengr]

In underground mining and coal ground fault protection is required. They use high resistance grounding. So unlike solidly grounded 480/277 we pick say 15 A and install a resistor connected to the neutral that guarantees under 15 A.

As far as ground fault detection and tripping many breakers and relays can do it. With the above resistor you can measure current with a CT or measure voltage across the resistor. Elsewhere you can use a CT with a large enough window to pass all 3 phases through it. Or you can use three phase CTs connected together for the return path as a “wye” arrangement. Current on the wye is ground fault current. Or you can measure all three phases and electronically add them as vectors which again equals the ground current.

Take a look at say an SEL-751 or SEL-710 for some top end relay examples. Or a Masterpact NW breaker with a series 6.0 trip unit. Or a Carlos Gavazzi relay. All of these easily do ground fault protection.

One of the interesting applications is high resistance grounding is that touch hazards as far as phase to ground cease to be a concern.

 

[kwired]

In underground mining and coal ground fault protection is required. They use high resistance grounding. So unlike solidly grounded 480/277 we pick say 15 A and install a resistor connected to the neutral that guarantees under 15 A.

As far as ground fault detection and tripping many breakers and relays can do it. With the above resistor you can measure current with a CT or measure voltage across the resistor. Elsewhere you can use a CT with a large enough window to pass all 3 phases through it. Or you can use three phase CTs connected together for the return path as a “wye” arrangement. Current on the wye is ground fault current. Or you can measure all three phases and electronically add them as vectors which again equals the ground current.

Take a look at say an SEL-751 or SEL-710 for some top end relay examples. Or a Masterpact NW breaker with a series 6.0 trip unit. Or a Carlos Gavazzi relay. All of these easily do ground fault protection.

One of the interesting applications is high resistance grounding is that touch hazards as far as phase to ground cease to be a concern.

But you shouldn't get too dependent on that not being a concern either. If there is a ground fault condition and you are not aware of it, you kind of have similar situation as if it were corner grounded delta if you happen to touch a phase conductor.

 

[yesterlectric]

UL me say one thing but whenever the NEC reference is a GFCI it is always a class a device that has a 6 mA threshold. Other equipment with higher threshold’s is referred to as GFPE for ground fault protection of equipment. This may provide some secondary personnel protection but it’s not referred to as gfci in code requirements language.

 

[wireday]

This equipment is a portable liquid heater, it’s on wheels, it will require a receptacle,in a manufacturing plant damp/wet area. I may try one of the devices to get 6ma gfci protection, Would you just install a 4 square and a 480 volt twist lock receptacle?

 

[romex jockey]

UL me say one thing but whenever the NEC reference is a GFCI it is always a class a device that has a 6 mA threshold. Other equipment with higher threshold’s is referred to as GFPE for ground fault protection of equipment. This may provide some secondary personnel protection but it’s not referred to as gfci in code requirements language.

from Winnie's link>>>
Although the new classes of devices trip at higher current levels (20 mA instead of 6 mA), UL calls these devices GFCIs, which UL defines as “a device intended for the protection of personnel.”

Looks like they've reconsidered Josh

~RJ~

 

[wireday]

from Winnie's link>>>
Although the new classes of devices trip at higher current levels (20 mA instead of 6 mA), UL calls these devices GFCIs, which UL defines as “a device intended for the protection of personnel.”

Looks like they've reconsidered Josh

~RJ~

GFCIstore.com has a GFCI model with selectable 6-10-30 ma settings.

 

[hillbilly1]

This equipment is a portable liquid heater, it’s on wheels, it will require a receptacle,in a manufacturing plant damp/wet area. I may try one of the devices to get 6ma gfci protection, Would you just install a 4 square and a 480 volt twist lock receptacle?

It probably won’t provide personnel protection from accidental contact, but would shut down a defective piece of equipment, but I think you will have a lot of nuisance tripping at the lower current threshold. Bonding and grounding would be more effective than gfci in this case. If current comes from another source, such as another piece of equipment with a ground fault, the gfci will not trip anyway for the liquid heater.

 

[kwired]

It probably won’t provide personnel protection from accidental contact, but would shut down a defective piece of equipment, but I think you will have a lot of nuisance tripping at the lower current threshold. Bonding and grounding would be more effective than gfci in this case. If current comes from another source, such as another piece of equipment with a ground fault, the gfci will not trip anyway for the liquid heater.

Assuring bonding is good is the best thing you can do with this thing.

Unlike 5-15 and 5-20 cord caps I never seen a missing EGC pin on a twist lock plug, that is a big thing also.