Motor Disconnects "9 m insight" CSA code rule

[majesus]

I have a question about motor disconnects, this is a CSA code question, but it may also apply to the NEC (430.102(b)) as well:

CSA code rule 28-604 (3)(a) states:
Motor disconnecting means shall be within sight of and within 9 m of the motor.

Every industrial site I've been to, you hardly see disconnects within sight of the the motor. The disconnects are usually in the MCC. So is this rule enforced?

A SLD of a new plant went out to the customer and they came back asking why are all these disconnects here? When rule 28-604 (3)(a) was explained, they replied we never had them there before.

There was a discussion about it with several engineers, where the same observation was mentioned, "that would be a lot of disconnects." Since the rule is to insure that the person(s) working on the motor would know it is disconnected from the power source. One fact came out of the discussion is that industrial plant have qualified electricians who are practicing "Lock out/Tag Out" procedures and the rule may have been omitted in those cases.

I was wondering if this a "new" rule, so I went back and looked at the CSA 2002 code book. Sure enough it states the samething.

Anyone can shed some light?

 

[resqcapt19]

In the NEC there is an exception that permits the controller disconnect, provided it is "lockable", to serve as the motor disconnect even where it is not within sight of the motor (15 m). Prior to the 2002 code there were few restrictions on the use of the exception. Under the 2002 and newer codes the exception is limited to industrial installations with written lockout procedures.

 

[itsmoked]

What I see is if it is a machine people work with, or use, it needs the local disconnect.

If it is something like an enclosed blower no one 'uses' then the lockable remote is acceptable.

I guess the logic is you need a local disconnect for safety. Like a guy gets caught in the machine.

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[waross]

Back in '86, rule 28-606, subrule (3).
By special permission where a trained and qualified electrical maintenance staff is available,............may be installed out of site of or more than 9 m from...
In 1990 this was changed to the present wording in subrule (4).
.....and it can be demonstrated that the location specified in subrule (3) is clearly impracticable.
Given the number of installations that are in violation of subrule (3) I suspect that "The customer doesn't want to pay for that." may be an acceptable demonstration of impracticability.
And, when the old supervisor who is a little out of his field and not up on current codes but has control of the future of junior engineers says
"that would be a lot of disconnects." politics takes precedence and code compliance and good engineering practice sometimes go out the window.
However, consider that OSHA, and in Canada, WCBs have requirements for safe work practices. When these requirements specify that the worker must ensure or verify that the proper circuit has been locked out, compliance may be very difficult and at times virtually impossible without local disconnects.


Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[majesus]

Perfect Waross... great info, a history lesson is exactly what I needed

Very interesting info. Much appreciated!

 

[lansford]

Also note that for medium voltage motors the code (NEC) thankfully does not require a local disconect. This would be a big expense and a problem!
JIM

 

[majesus]

Bringing this up again (in highlight of the CEC)

Until this morning I was firmly convinced (from my CEC course and discussion here) that it is a requirement that motors must follow this rule. However, someone early today pointed out to me the “OR” in 28-604(1)(b)(i) of the CEC 2006.

Where it states (and I bolded the important part)

28-604 Location of disconnecting means from CEC 2006
(1) Motor branch circuit disconnecting means described in Rule 28-602(1)(a), (b), (c), and (d) shall
(a) be located at the distribution centre from where the motor branch circuit originates; and
(b) where intended to serve as a single disconnecting means for a motor branch circuit, motor, and
controller or starter shall also be
(i) located in accordance with Subrule (3); or
(ii) capable of being locked in the open position by a lock-off device approved for the purpose and
be clearly labelled to describe the load or loads connected.

(2) Motor branch circuit disconnecting means described in Rule 28-602(1)(f) shall be located in accordance
with Subrule (3).
(3) Except as required in Subrule (5), motor and motor starter or controller disconnecting means shall be
located
(a) within sight of and within 9 m of the motor and the machinery driven by it; and
(b) within sight of and within 9 m of the motor starter or controller


So it now seems that through interpretation: that if the disconnect means is capable of being locked in the open position by a lock off device approved for the purpose and clearly labelled to describe the load it is connected, then the 9m within sight rule does not apply.