Double pole switch in lieu of disco

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follybeacher

Member
Location
USA
Occupation
Estimator
I often see discos diagrammatically shown on plan but the intent may be simply means of disconnect... any issues with using a double pole switch (lets say either a 240V/20A or 30A for sake of discussion) with a flex whip and term to the equipment? This assembly would be applied to exhaust fans, VAVs, etc in accessible ceilings typically.

As shown in the pic EEs typically show a switch for 120V/20A means of disconnect so I figured I'd ask the hive. Thanks!


Capture.jpg
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
Nothing wrong with using Dp switches (208/240) v or sp switches (120/ 277) for controlling fans, etc. As long as a fuse is not mentioned on the nameplate the switches will work.
 

follybeacher

Member
Location
USA
Occupation
Estimator
Great! Just trying to save cost while maintaining intent of design and code compliance. These little things help.
 

kwired

Electron manager
Location
NE Nebraska
Some of those pull out AC disconnects cost less than a 2 pole toggle switch, box and cover. Sometimes the switch, box and cover might be more practical though.
 

KnightPower

Member
Location
US
I agree a pullout resi disconnect cost half what a 30A DP switch in 4" square does.

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KnightPower

Member
Location
US
Cool. I totally agree I prefer a DP toggle.. one on my WH in basement. I was replying to OP.

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cdslotz

Senior Member
Be sure to check all mechanical specs and schedules. A lot of those units are specified to have factory disconnects included
 

follybeacher

Member
Location
USA
Occupation
Estimator
Be sure to check all mechanical specs and schedules. A lot of those units are specified to have factory disconnects included

this is good advice and I do check and qualify as such

I often forget about those resi pull out discos. I imagine they can't be installed in anything other than multifamily or resi... for example commercial applications where specs call out general duty safety switches or such?
 

jumper

Senior Member
this is good advice and I do check and qualify as such

I often forget about those resi pull out discos. I imagine they can't be installed in anything other than multifamily or resi... for example commercial applications where specs call out general duty safety switches or such?

If specs called for such-yes but those pull out discos are certainly used in commercial a lot.

They are not limited to resi applications.
 

cdslotz

Senior Member
If specs called for such-yes but those pull out discos are certainly used in commercial a lot.

They are not limited to resi applications.

Most commercial specs require heavy duty safety switches, so resi pull-outs would not be accepted
 
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