# Poles

[Alwayslearningelec]

I get confused by phases/# of poles sometimes depending application.
I have 1 phsse motor that needs motor rated toggle. Wouldn't I need 1 pole switch.

All I ever see I ever see is 2 poles. A 2 pole wouldn't work with a 1 phase motor, correct?

 

[roger]

Single phase can be two hots or one hot and neutral. So depending if the switch will be used as a controller or disconnect can determine what you need on two hots.

 

[SceneryDriver]

And if the motor is 120V, either wire both the hot and neutral through the 2-pole switch (my preference), or just use one pole and switch only the hot.


SceneryDriver

 

[Jraef]

The only thing you cannot do in a 120V circuit is switch only the neutral (grounded conductor). Technically it would function, but sets up a dangerous situation.

Hot only, or hot + neutral together.

Neutral without the hot, never.

 

[infinity]

I get confused by phases/# of poles sometimes depending application.
I have 1 phase motor that needs motor rated toggle. Wouldn't I need 1 pole switch.

You can't just use a simple HP rated 20 amp toggle switch?

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[augie47]

From your attached photos FCU13 looks like a 115v motor in which case 2 pole switch could be used but not necessary.
I'm not sure if the attached photo on switches are manual motor starters or not. It may be one of those types is needed to provide OL protection for the motor

 

[infinity]

From your attached photos FCU13 looks like a 115v motor in which case 2 pole switch could be used but not necessary.
I'm not sure if the attached photo on switches are manual motor starters or not. It may be one of those types is needed to provide OL protection for the motor

Good point. The symbol for a thermal switch is typically an ST next to the unit. I see a switch symbol on his drawing but no T. For units this size I would think that they are internally thermal protected.

 

[augie47]

Good point. The symbol for a thermal switch is typically an ST next to the unit. I see a switch symbol on his drawing but no T. For units this size I would think that they are internally thermal protected.

 

[jaggedben]

Poles simply refers to the number of wires you are switching. Usually (but not 100% always) you switch all the hots that are present, and only those hots. This has no particular relationship to the number of phases in the circuit or system.

 

[mtnelect]

In condensing units, the contactors are single pole with the other pole a solid link.

 

[LarryFine]

In condensing units, the contactors are single pole with the other pole a solid link.

 

[augie47]

Note that doing so is fine for a controller but not a disconnecting means. The disconnect must open all phase conductors.

 

[jaggedben]

Note that doing so is fine for a controller but not a disconnecting means. The disconnect must open all phase conductors.

Just say 'ungrounded'.

 

[augie47]

Just say 'ungrounded'.

my bad 430.103 does say "ungrounded"

 

[Eddie702]

HVAC unit are built to save every penny so they go with single pole contactors.

As far a switches go my understanding is (except for very small motors) that you use a HP rated switch and there are toggle switches rated in HP or you have to use a switch rated double the motor amps.

 

[Knightryder12]

As others have said above, this motor is 120V, so just use a 20a motor rated snap switch. Its all you need for a local disconnecting means.

 

[Alwayslearningelec]

You can't just use a simple HP rated 20 amp toggle switch?

Hubbell HBL1221W Wall Swtch,1-Pole,120/277V,20A,Wht,Toggl | Zoro.com

Order Hubbell Wall Swtch, 1-Pole, 120/277V, 20A, Wht, Toggl, HBL1221W at Zoro.com. Great prices & free shipping on orders over $50 when you sign in or sign up for an account.

www.zoro.com

Yea that may be fine.