Disconnecting mean for AHU's

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slock

Member
Senario is 10 KW heat strips in AHU with a 3/4 HP motor>>>>>>

anyone excepting breaker lockouts in lue of a disconnect at unit

keep in mind OCD is out of sight
 

bdarnell

Senior Member
Location
Indianapolis, IN
Occupation
Retired Engineer
I'm OK with it as long as the locking means is installed on the breaker to lock it in the open position. No fair using Brady lockout kits that you can take with you. :D
 

Cavie

Senior Member
Location
SW Florida
The 6' rule is gone I am sorry to say. Took it out in 2002. Lockouts are ok I am also sorry to say. I was forced to give up that fight.
 

bdarnell

Senior Member
Location
Indianapolis, IN
Occupation
Retired Engineer
Cavie said:
The 6' rule is gone I am sorry to say. Took it out in 2002. Lockouts are ok I am also sorry to say. I was forced to give up that fight.

Even though the rule exists, very rarely, ef ever, will you find a piece of rooftop equipment installed these days without a disconnect at the unit. Most design engineers (myself included) put it on the drawings as a matter of course. I even go one step further on my D & B projects and require the HVAC contractor to provide a factory installed disconnect and factory installed and wired GFCI receptacle. It doesn't add much to the cost of the unit and makes everyone's life a lot easier.
 

Cavie

Senior Member
Location
SW Florida
A/C and Ref equipment must have disc within sight. 440.14. I don't know why an A/H unit doens't need it. I don't wright 'em I just reads 'em.
 

LOCKELECT

Member
Location
FLORIDA
Ref: 424.19 (A) (2) (2002 NEC) disconnecting means

Ref: 424.19 (A) (2) (2002 NEC) disconnecting means

Referring to 424.19 (A) (2),
"2) Heater Containing a Motor(s) Rated Over 1/8 Horsepower. The above disconnecting means shall be permitted to serve as the required disconnecting means for both the motor controller(s) and heater by one of the means specified in items (1) through (4):
(1) Where the disconnecting means is also in sight from the motor controller(s) and the heater.
(2) Where the disconnecting means is not within sight from the heater, a separate disconnecting means shall be installed, or the disconnecting means shall be capable of being locked in the open position, or unit switches complying with 424.19(C) shall be permitted.
(3) Where the disconnecting means is not within sight from the motor controller location, a disconnecting means complying with 430.102 shall be provided.
(4) Where the motor is not in sight from the motor controller location, 430.102(B) shall apply. "

INTERPRETATION IS THAT A LOCKOUT COULD BE UTILIZED FOR THE HEAT, BUT IF YOU LOOK AT 430.102 THE LOCK OUT COULD NOT SERVE AS THE DISCONNECT FOR THE MOTOR CONTROLLER (CONTACTOR) BECAUSE THE EXCEPTIONS (A) & (B) ARE NOT MET {MOST MUNICIPALITIES DO NOT REQUIRE QUALIFIED INDIVIDUALS ON THE JOB)
 

augie47

Moderator
Staff member
Location
Tennessee
Occupation
State Electrical Inspector (Retired)
[]INTERPRETATION IS THAT A LOCKOUT COULD BE UTILIZED FOR THE HEAT, BUT IF YOU LOOK AT 430.102 THE LOCK OUT COULD NOT SERVE AS THE DISCONNECT FOR THE MOTOR CONTROLLER (CONTACTOR) BECAUSE THE EXCEPTIONS (A) & (B) ARE NOT MET {MOST MUNICIPALITIES DO NOT REQUIRE QUALIFIED INDIVIDUALS ON THE JOB)[/size]
That is the way I would approach it also
 
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