Devices without neutrals

[Aaron Folk]

I'm prepping for my journeyman's exam (2023 NEC) and just got caught on a question for service neutral calculations. Apparently water heaters don't have neutral conductors. Are there any other common devices/appliances that don't use neutrals that I should know about?

Thanks in advance.

 

[Fred B]

Mini-splits. But, it has both a neutral and non-neutral, sending neutral current onto the EGC. But off course that is why they are tripping the GFCI.

 

[infinity]

Most outdoor AC units and blowers are 240 volts. Some electric heat is also 240 volts.

 

[augie47]

A lot of 240v equipment does not require a neutral. HVAC unit heaters, condensers, kitceh appliance just to name a few

 

[ActionDave]

240V well and irrigation pumps.

 

[petersonra]

Most 3 phase loads do not use a neutral.

 

[jaggedben]

Some solar inverters. Some energy storage systems.

 

[Eddie702]

Electric baseboard

 

[zbang]

So ya, there are many common devices that don't use the neutral.

Since we're on the subject- be careful with the word neutral, look at the definitions in Art 100 of that and grounded conductor, then follow that to system grounding in Art 250 part II.

 

[letgomywago]

Remember when doing the optional calculations you do the nuetral standard

 

[curt swartz]

Mini-splits. But, it has both a neutral and non-neutral, sending neutral current onto the EGC. But off course that is why they are tripping the GFCI.

Never seen one that used the EGC as a current carrying conductor. The issue with mini splits and newer high efficiency A/C condensers is the VFD running the compressor.

 

[winnie]

Never seen one that used the EGC as a current carrying conductor. The issue with mini splits and newer high efficiency A/C condensers is the VFD running the compressor.

Agree.

The minisplit is not using the EGC as an intentional part of the circuit.

The EGC is a path for the leakage current caused by the VFD high frequency switching and the parasitic capacitance between compressor and housing.

Jon

 

[Fred B]

Never seen one that used the EGC as a current carrying conductor. The issue with mini splits and newer high efficiency A/C condensers is the VFD running the compressor.

Indoor unit of the cheap DIY from the big box had 120 run from the power feeder to the compressor and 240 for the compressor and no neutral connection terminal from the panel feed. Neutral and ground bonded within the compressor unit connections bus.

Unless they've recently changed

 

[winnie]

Indoor unit of the cheap DIY from the big box had 120 run from the power feeder to the compressor and 240 for the compressor and no neutral connection terminal from the panel feed. Neutral and ground bonded within the compressor unit connections bus.

Unless they've recently changed

Yuck. That shouldn't have an NTRL listing and shouldn't be installed. That would absolutely trip a GFCI.

Jon

 

[Paul_Briganti]

Level 2 Car Chargers...

 

[JouleJester]

Huh, some curious forum I would say. Just a follow up question, how to tackle question considering the calculation of service neutral size?
Does it usally depends on the type of service or load ?!

 

[LarryFine]

In a home, the range and dryer are just about the only line-to-line loads that do use the neutral.

 

[ggunn]

In a home, the range and dryer are just about the only line-to-line loads that do use the neutral.

What about HVAC systems?

 

[LarryFine]

What about HVAC systems?

Every one I have ever wired is either 120v (gas-heat air handler) or 240v (everything else).

 

[jaggedben]

Huh, some curious forum I would say. Just a follow up question, how to tackle question considering the calculation of service neutral size?
Does it usally depends on the type of service or load ?!

See 220.61.
One should be allowed to ignore line-line loads when doing a load calc to size a feeder or service neutral. In my experience, this is never done in residential work, meaning most residential service or feeder neutrals are oversize. Commercial may be different.