Disconnect switches for your equipment

[woodchucker]

Early on I tried hard wiring some of my machines. As time went on, I realized it wasn't going to work all that well since I kept adding machines and rearranging things to get them all to fit. I finally decided to use outlets strategically placed in the ceiling and soft power cords with appropriate plugs.

Here are a few pictures of some machines with the cords going to the ceiling mounted outlets. All machines use either 12 ga or 10 ga wires. It's not necessary for the amperage load, but more so because of the type of insulation available. Some outlets use twist lock plugs while others use standard 20 amp or 50-amp grounded plugs. Note these pictures were taken in 2018. Since then, at least 3 more machines have been added and the floor plan has been rearranged at least twice.

nice looking shop there projectnut.

 

[mksj]

NEC Sec. 430.122(A), circuit conductors for an adjustable-speed drive system must have an ampacity of not less than 125% of the rated input current to the power conversion equipment. I am not aware of any specifications as to type of use. My understanding is it has more to do with the maximum duty capabilities of the VFD, and too safe guard the wiring should the motor be changed to something different. It also has to do with providing sufficient headroom when the VFD is run in an overload scenario which can be up to 200% or more of rated output for short periods of time. Not an electrician, just what I have read and seems to be continually referenced. There is also local code which may have other requirements.

Stumped by the Code? NEC Requirements for Sizing Conductors That Feed an Adjustable-Speed Drive System

Answering your NEC questions.

www.ecmweb.com

I would refer back the the lathe manufacturer as to the required wiring and recommended single phase breaker size for the power to the lathe. I will say, that a single phase 30A is not sufficient for this size VFD/motor. I have done a number of VFD systems with Yaskawa drives and for a 5 Hp motor, they usually they are run off of a single phase 50A breaker. The input current for the Yaskawa 0030 model is 24A at 240VAC (3 phase), on 3 phase it would require a 30A three pole breaker, on single phase would be ~40A x 125% = 50A. I have not seen how one address it being run in derated mode, breaker fusing is also affected by if you are using a DC choke (DCR) which decreases the current pulses, so they will lower the fusing breaker requirements when used. Example below is from the Fuji manual.

In addition if you do use a receptacle, current NEC code states GFCI protection is required for all 125-volt to 250-volt receptacles rated 50 amps or less, not exceeding 150 volts to ground, supplied by a single-phase branch circuit in the following:
Basements, all areas, including unfinished portions
Bathrooms, all areas
Crawlspaces, all areas
Garages, including service bays and similar areas, but not show rooms and exhibition halls
Indoor wet locations, all areas
Kitchens, all areas, as well as other rooms for cooking or food or beverage preparation, such as break rooms
Locker rooms, all areas with showers
Outdoors, all areas
All areas with sinks. Not required for industrial laboratory sinks where the removal of power would introduce a greater hazard.

GFCI protection is required for all areas of rooftops of non-dwelling units. GFCI receptacles must be installed within 25 feet of heating, air conditioning and refrigeration equipment and readily accessible from the rooftop’s surface area.

I would hardwire the lathe so you do not need to get an expensive GFCI Breaker, and they tend to not play nice with VFD's.

 

[rabler]

NEC Sec. 430.122(A), circuit conductors for an adjustable-speed drive system must have an ampacity of not less than 125% of the rated input current to

Thanks for the NEC reference. 125% it is.

 

[rabler]

(moved to a separate thread)

 

[jareese]

NEC Sec. 430.122(A), circuit conductors for an adjustable-speed drive system must have an ampacity of not less than 125% of the rated input current to the power conversion equipment. I am not aware of any specifications as to type of use. My understanding is it has more to do with the maximum duty capabilities of the VFD, and too safe guard the wiring should the motor be changed to something different. It also has to do with providing sufficient headroom when the VFD is run in an overload scenario which can be up to 200% or more of rated output for short periods of time. Not an electrician, just what I have read and seems to be continually referenced. There is also local code which may have other requirements.

Stumped by the Code? NEC Requirements for Sizing Conductors That Feed an Adjustable-Speed Drive System

Answering your NEC questions.

www.ecmweb.com

I would refer back the the lathe manufacturer as to the required wiring and recommended single phase breaker size for the power to the lathe. I will say, that a single phase 30A is not sufficient for this size VFD/motor. I have done a number of VFD systems with Yaskawa drives and for a 5 Hp motor, they usually they are run off of a single phase 50A breaker. The input current for the Yaskawa 0030 model is 24A at 240VAC (3 phase), on 3 phase it would require a 30A three pole breaker, on single phase would be ~40A x 125% = 50A. I have not seen how one address it being run in derated mode, breaker fusing is also affected by if you are using a DC choke (DCR) which decreases the current pulses, so they will lower the fusing breaker requirements when used. Example below is from the Fuji manual.
View attachment 443687
In addition if you do use a receptacle, current NEC code states GFCI protection is required for all 125-volt to 250-volt receptacles rated 50 amps or less, not exceeding 150 volts to ground, supplied by a single-phase branch circuit in the following:
Basements, all areas, including unfinished portions
Bathrooms, all areas
Crawlspaces, all areas
Garages, including service bays and similar areas, but not show rooms and exhibition halls
Indoor wet locations, all areas
Kitchens, all areas, as well as other rooms for cooking or food or beverage preparation, such as break rooms
Locker rooms, all areas with showers
Outdoors, all areas
All areas with sinks. Not required for industrial laboratory sinks where the removal of power would introduce a greater hazard.

GFCI protection is required for all areas of rooftops of non-dwelling units. GFCI receptacles must be installed within 25 feet of heating, air conditioning and refrigeration equipment and readily accessible from the rooftop’s surface area.

I would hardwire the lathe so you do not need to get an expensive GFCI Breaker, and they tend to not play nice with VFD's.

I am planning on hard wiring it. I have a double pole 30 amp on it now, you're saying I need to bump that up to 50 amp? I will do so if needed.

 

[mksj]

Wiring and breaker recommended should be ~50A, and should be specified by manfacturer. The input current for the Yaskawa single phase VFD (BA0018) 5Hp V1000 is 35A, the (2A0030) is 3 phase input at 24A (or ~40A single phase), but the VFD is run in a derated mode. The recommended minimum branch circuit breaker is the VFD rated input current x 125%. So the minimum breaker size would be ~43A and you would round up to the nearest breaker size. I run the Yaskawa V1000 2A0020 in derated mode on a 3 Hp motor and use a 30A single phase breaker. You already have fusing in the machine electrical cabinet to protect the components.

 

[jareese]

Wiring and breaker recommended should be ~50A, and should be specified by manfacturer. The input current for the Yaskawa single phase VFD (BA0018) 5Hp V1000 is 35A, the (2A0030) is 3 phase input at 24A (or ~40A single phase), but the VFD is run in a derated mode. The recommended minimum branch circuit breaker is the VFD rated input current x 125%. So the minimum breaker size would be ~43A and you would round up to the nearest breaker size. I run the Yaskawa V1000 2A0020 in derated mode on a 3 Hp motor and use a 30A single phase breaker. You already have fusing in the machine electrical cabinet to protect the components.

I installed a 50 amp dual pole, Thanks Mark.