disconnect switch by motors

[alexlavitt]

What is the code referencing a disconnect switch must be installed by all electrical motors?
I have a stubborn client refusing to install switches on his 3phase 460volt system, someone could get hurt badly.

 

[raider1]

Welcome to the forum.

Take a look at Part IX of Article 430. Specifically 430.102(A) and (B).

Chris

 

[mkgrady]

What is the code referencing a disconnect switch must be installed by all electrical motors?
I have a stubborn client refusing to install switches on his 3phase 460volt system, someone could get hurt badly.

Ask him to picture himself on the stand describing why the injured maintenance man should not have a piece of his net worth.

 

[wawireguy]

Is this job getting inspected?

 

[Cold Fusion]

What is the code referencing a disconnect switch must be installed by all electrical motors?
I have a stubborn client refusing to install switches on his 3phase 460volt system, someone could get hurt badly.

There isn't one. In fact most of the stuff I work does not have a disconnect near (in sight of) the motor. I only know of a few cases where a switch was installed next to the motor. They were all conveyors that jammed easily, required someone get in there and pull out the offending rip-rap. The switches were put in for convenience of maintence. It was easier to turn off the disconnect than go down to the MCC room and lock it out.

I'm curious, what is there about this job that requires a local disconnect for safety.

cf

 

[alexlavitt]

Found the answer

Found the answer

Thank you all for responding so quickly.
It is a car wash and the contractor did not install any disconnect switches to cut cost.
NEC 110.58 (Disconnecting Means) reads:
"You must have a disconnect within sight of each transformer or motor. This allows a person to lock out the transformer or motor for maintenance, or to shut it off quickly in case of misoperation."
I found this on:
http://www.codebookcity.com/codearticles/nec/necarticle110.htm

 

[mkgrady]

I'm curious, what is there about this job that requires a local disconnect for safety.

cf

NEC requires a disconnect for a motor to be within 50 feet and within sight of the motor

 

[Cold Fusion]

NEC requires a disconnect for a motor to be within 50 feet and within sight of the motor

Not that I can tell.

Chris' references are the guiding principles. Probably 99.99% of the stuff I work falls under 430.102.B.2 Exception.

cf

 

[Cold Fusion]

NEC requires a disconnect for a motor to be within 50 feet and within sight of the motor

mk -
One other thing I'm curious about. Where is this "within 50 feet" requirement mentioned. I don't recall ever seeing that in the NEC.

Well, except for the definitions of course:roll:

cf

 

[rbalex]

Thank you all for responding so quickly.
It is a car wash and the contractor did not install any disconnect switches to cut cost.
NEC 110.58 (Disconnecting Means) reads:
"You must have a disconnect within sight of each transformer or motor. This allows a person to lock out the transformer or motor for maintenance, or to shut it off quickly in case of misoperation."
I found this on:
http://www.codebookcity.com/codearticles/nec/necarticle110.htm

Codebook City blew it big time on this one. Section 110.58 applies to Tunnel Installations over 600 Volts, Nominal, not a carwash.

However, you were given the proper references by Chris (raider1). Read it carefully. The rule doesn't require a disconnect immediately next to the motor; but, with few exceptions and depending on which NEC edition is effect, it does require a disconnect "in sight from" both the motor and driven equipment. ​

 

[W6SJK]

It's pretty simple... 430.102 (B) requires the motor disconnect unless the disconnect provided at the controller (starter) per 430.102 (A) is capable of being locked open, which most are. See the exception to 430.102 (B) assuming 2008 NEC.

The 50 ft value is given in the Article 100 definition for "within sight from."

 

[iwire]

It's pretty simple... 430.102 (B) requires the motor disconnect unless the disconnect provided at the controller (starter) per 430.102 (A) is capable of being locked open, which most are. See the exception to 430.102 (B) assuming 2008 NEC.

I have to strongly disagree here, you almost always have to have a disconnecting means in sight of the motor.

In order to use that exception to 430.102(B) you have to meet either condition (a) or (b) of the exception

To meet condition (a) a disconnect at the motor would have to increase the hazards to people or property (kind of unlikely) or it would have to be 'impracticable'.

Impracticable is not the same as impractical, impracticable means that something can not be done. Like trying to have a disconnecting means within 'sight' of a submersible pump. that would be impracticable.

To meet condition (b) will be up to the AHJ.

 

[W6SJK]

I have to strongly disagree here, you almost always have to have a disconnecting means in sight of the motor.

Thanks iWire! I agree. I'm living in the past. I see that rule was changed in 2002 and I had forgotten because I always put a disconnect at the motor and hadn't looked that up in quite a while obviously. And to make matters worse, when I checked my 2008 code PDF the (a) and (b) conditions were on the next page of the PDF and I didn't even notice them. My bad.

 

[pfalcon]

Ask him to picture himself on the stand describing why the injured maintenance man should not have a piece of his net worth.

Ask him to talk to mom when the motor grinds up the child that walked into the area while he was reconnecting the machine. That's why the it includes "and the driven equipment" as well as the motor. You got to turn that thing back on once you get it fixed.

 

[charlie b]

I'm curious, what is there about this job that requires a local disconnect for safety.

There need not be anything special about this particular job. The local disconnect is all about safety, and applies to most situations. I believe its purpose is to allow the maintenance person to have the additional confidence that nobody is about to reenergize the motor while it is being serviced. That is why the local disconnect must be within sight. It is the same reason that there must be a local disconnect near a piece of HVAC equipment.

I don't think that anything requires that the local disconnect be the item that is tagged out during maintenance. The tag could just as well be placed at the MCC, even if the MCC is in another room. If it were me doing the maintenance, I would prefer to have a tag on the local disconnect as well as at the power source. But if I were to see someone standing near the local disconnect, I would probably remove my hands from the motor, and ask the other person what they are doing there.

 

[Cold Fusion]

.... The local disconnect is all about safety, and applies to most situations. I believe its purpose is to allow the maintenance person to have the additional confidence that nobody is about to reenergize the motor while it is being serviced. That is why the local disconnect must be within sight. ....

I would agree completely if you had said, "The local disconnect is all about safety during maintenance ..."

cf

 

[Cold Fusion]

Ask him to talk to mom when the motor grinds up the child that walked into the area while he was reconnecting the machine. That's why the it includes "and the driven equipment" as well as the motor. You got to turn that thing back on once you get it fixed.

pf, mk -
First, a disclaimer: I don't build or design carwashes. So maybe there is sneaky, dangerous stuff going on that I don't know about - and I'm all wet:roll:

Let's think about this a minute.

If you put in a disconnect, the code requires it to be, "in sight from the motor location and driven machinery location". The few times I've put them in they were right next to the motor and yes you could see the driven machinery.

So, the operator gets an emergency and runs down to the end of the conveyor and shuts off the motor disconnect. Not a good idea. Especially if there is more than one disconnect and the operator, in a panic, grabs the wrong one.

So, here is my design (carwash ignorant person that I am):
The operator gets an emergency and reaches out and slaps the E-stop button - all the conveyors/pumps/driven machinery immediately stops. No waiting for the operator to run to the other end. No finding multiple disconnects to stop all of the machinery.

But wait, suposing the operator is on the other side - okay I'll put a butt in over there as well. But wait, the operator can be any where along this area - okay, Ill put up a pull rope.

There are a lot better ways than a disconnect switch to provide for general safety shutdown.

Please note I'm not suggesting to not install a disconnect. If the install does not meet 430.102.B Exception, the put in the disconnect. I just would not count on it for a general safety shutdown - that's what the E-stops are for.

cf

 

[charlie b]

I would agree completely if you had said, "The local disconnect is all about safety during maintenance ..."

In that case, let me correct my previous statement to say that, "The local disconnect is all about safety during maintenance ...."

I agree that it has no safety function during normal operation. It is not required to be able to function as an emergency shutoff, for example. It is not impossible that one might be used in that way, but that is not why it is there. I would not be adverse, for example, to seeing one locked in the closed position during normal operation.

 

[pfalcon]

In that case, let me correct my previous statement to say that, "The local disconnect is all about safety during maintenance ...."

I agree that it has no safety function during normal operation. It is not required to be able to function as an emergency shutoff, for example. It is not impossible that one might be used in that way, but that is not why it is there. I would not be adverse, for example, to seeing one locked in the closed position during normal operation.

Primary purpose: Remove power for service
Secondary purpose (per NFPA79): Category 0 stop - Cannot be locked ON/Closed unless another category 0 stop is provided. [Instant total power deprivation]
Not a listed purpose: Emergency stop function

Purpose for "in sight of": Observation of motor and driven machinery during the operation of the disconnect, both opening and closing. It is not for observing during service since during that time it should be locked out. This is so you can observe that the equipment does not create a hazard while operating the disconnect.

 

[Cold Fusion]

I have to strongly disagree here, you almost always have to have a disconnecting means in sight of the motor.

In order to use that exception to 430.102(B) you have to meet either condition (a) or (b) of the exception

To meet condition (a) a disconnect at the motor would have to increase the hazards to people or property (kind of unlikely) or it would have to be 'impracticable'.

Impracticable is not the same as impractical, impracticable means that something can not be done. Like trying to have a disconnecting means within 'sight' of a submersible pump. that would be impracticable. ...

FPN 1, right below 430.102.B.2 Exception, gives some insight on what the NEC considers "additional or increased hazards". It appears to be significantly less rigid than your interpretation. In the industries I work, disconnect switches at the motor are just not common. And I've never heard of an AHJ squawking about that.

...To meet condition (b) will be up to the AHJ.

Never even heard of an AHJ questioning a written LOTO.

However, as I said earlier: I don't have any experience with carwashes - my experience is industrial. I do not insist that what is right for the industry I'm in is also right for a carwash.

cf