Simple motor controller question.

[darekelec]

Hi, guys.
I did not have experience with motors for the past few years and tomoro i will have to install a timer for 5 amp 120v indoor exhaust fan. that would make it 1/4 hp i guess.
the timer is going to be adjacent to fan and it's disconnect in commercial application.
my Q is;
is that timer concidered a controller and does it have to have disconnect? i wanted to install a decora style device for motor loads. if it has integral off option would that count?
i could have it on load side of motor disco but that would knock it off real time or reset after turning disco off.
thanks for this forum and it's members

 

[jusme123]

Hi, guys.
I did not have experience with motors for the past few years and tomoro i will have to install a timer for 5 amp 120v indoor exhaust fan. that would make it 1/4 hp i guess.
the timer is going to be adjacent to fan and it's disconnect in commercial application.
my Q is;
is that timer concidered a controller and does it have to have disconnect? i wanted to install a decora style device for motor loads. if it has integral off option would that count?
i could have it on load side of motor disco but that would knock it off real time or reset after turning disco off.
thanks for this forum and it's members

the timer is a control device, not a disconnect. read 430.103(B)

 

[darekelec]

yes. a timer is a controller.
the fan to which i would like to add the timer to has already a disconnect.
my Q is
do I have to have the timer on load side of motor disconnect? toggle switch in my case.

 

[Buck Parrish]

For example if you had an attic fan on a timer and on a switch in the hall. When you go to the attic. You would still need one right next to it.
Their so many variations of installed motors though.

 

[Smart $]

yes. a timer is a controller.
the fan to which i would like to add the timer to has already a disconnect.
my Q is
do I have to have the timer on load side of motor disconnect? toggle switch in my case.

You have to have a disconnect for both the controller (timer) and the motor, within sight of respectively. However, the controller disconnect can serve as a disconnect for both if within sight of both and the driven machinery.

So what it amounts, if power to timer must be maintained at all times so as to not lose programming, the timer cannot be installed on the load side of the motor disconnect, and will require a separate disconnect to its line side.

Yet this leads to the question how the timer going to maintain programming during a power outage?

 

[darekelec]

What if my controller (timer) has an integral open all hot legs off manual button? Does that qualify as its disconnect?

 

[don_resqcapt19]

What if my controller (timer) has an integral open all hot legs off manual button? Does that qualify as its disconnect?

Does it disconnect the power to the controller? I think not, and the controller disconnect must disconnect the power to the controller.

 

[templdl]

Does it disconnect the power to the controller? I think not, and the controller disconnect must disconnect the power to the controller.

If I were to guess at what you are say a controller is two things come to mind:
An enclosed combination motor control consisting of a fused or breaker disconnect or n MCC bucket with a combination motor controller.
In either case they typically will have an electrical interlock on the door hand or on the disconnect itself that will open the control circuit when the door is open at the same time that the power is disconnected should the control power source be from outside of the enclosure. . Of course if the control power source is the from the bucket itself there is no need for the electrical interlock as the control power will be disconnect by the fused or breaker disconnect anyway.

 

[don_resqcapt19]

In combination starter, the breaker or fused switch is the disconnect and does disconnect the power to the controller (contactor).

I don't think anything in the rules in 430.102 address the disconnection of the control power. In my opinion those rules are aimed at the power that runs the motor.

 

[delectric123]

You have to have a disconnect for both the controller (timer) and the motor, within sight of respectively. However, the controller disconnect can serve as a disconnect for both if within sight of both and the driven machinery.So what it amounts, if power to timer must be maintained at all times so as to not lose programming, the timer cannot be installed on the load side of the motor disconnect, and will require a separate disconnect to its line side.Yet this leads to the question how the timer going to maintain programming during a power outage?

i assume the derekelec wants to install the fan in a residential building.so in other words the Bathroom fan timer of a house must have a disconnect in sight?

 

[Lectricbota]

i assume the derekelec wants to install the fan in a residential building.so in other words the Bathroom fan timer of a house must have a disconnect in sight?

The OP stated commercial application---don't know if I have seen many 1/4 hp bathroom fans in resi either.

 

[Smart $]

i assume the derekelec wants to install the fan in a residential building.so in other words the Bathroom fan timer of a house must have a disconnect in sight?

Well if you strictly adhere to Code, yes. But I won't tell the inspector if you don't comply... :lol:

 

[templdl]

In combination starter, the breaker or fused switch is the disconnect and does disconnect the power to the controller (contactor).

I don't think anything in the rules in 430.102 address the disconnection of the control power. In my opinion those rules are aimed at the power that runs the motor.

Greetings Don,
There appears to be a requirement included in NFPA 79 Electrical Standard for Industrial Machinery, 7 Supply circuit disconnect in means, 7.5 Supply conductors to be disconnected:
Each disconnecting means shall disconnect all ungrounded conductors of a single supply circuit simultaneously. Where there is more than one source, additional individual disconnecting means shall be provided for each supply circuit so that all supply to the machine may be interrupted.
The is an exception though which require that those circuits that remain energized be identified with yellow wiring as well as warning requirement such as signage stating the presents of separate control.

We used to included a yellow label on each door for enclosures wired as such
Dave

 

[don_resqcapt19]

Greetings Don,
There appears to be a requirement included in NFPA 79 Electrical Standard for Industrial Machinery, 7 Supply circuit disconnect in means, 7.5 Supply conductors to be disconnected:
Each disconnecting means shall disconnect all ungrounded conductors of a single supply circuit simultaneously. Where there is more than one source, additional individual disconnecting means shall be provided for each supply circuit so that all supply to the machine may be interrupted.
The is an exception though which require that those circuits that remain energized be identified with yellow wiring as well as warning requirement such as signage stating the presents of separate control.

We used to included a yellow label on each door for enclosures wired as such
Dave

Dave,
I don't think that NFPA 79 applies to a MCC or motor controller that is not part of "Industrial Machinery".

I am not even sure if it applies to PLCs that are used to control industrial processes. I have never seen the multiple disconnects at a PLC that would be required to disconnect the power from all of the contact ouputs used to control starters in an MCC. The internal wiring, though, for these contacts is yellow from the output to the terminal block where the field connections are made. The field wiring is multiple colors, but typically red and blue for a contact that runs a remote motor starter.

 

[templdl]

Dave,
I don't think that NFPA 79 applies to a MCC or motor controller that is not part of "Industrial Machinery".

I am not even sure if it applies to PLCs that are used to control industrial processes. I have never seen the multiple disconnects at a PLC that would be required to disconnect the power from all of the contact ouputs used to control starters in an MCC. The internal wiring, though, for these contacts is yellow from the output to the terminal block where the field connections are made. The field wiring is multiple colors, but typically red and blue for a contact that runs a remote motor starter.

Don,
Then is there a standard that can be referred to regarding control wiring?
NFPA 79 appears to be a well kept secret as I have found many that have never scene a copy of it or even know that bit exists.
I worked for a large MCC manufacturer and I agree on the color code that you had referred to, red being the basic bucket control circuit, yellow for separate control provided external to the bucked, and blue for DC. A yellow warning label was applied to the door warning of separate control.
Dave

 

[delectric123]

Don, Then is there a standard that can be referred to regarding control wiring? NFPA 79 appears to be a well kept secret as I have found many that have never scene a copy of it or even know that bit exists. I worked for a large MCC manufacturer and I agree on the color code that you had referred to, red being the basic bucket control circuit, yellow for separate control provided external to the bucked, and blue for DC. A yellow warning label was applied to the door warning of separate control.Dave

is there a place where these color codes are documented?

 

[Smart $]

is there a place where these color codes are documented?

In addition to NFPA 79 there's UL508A.

Here's a guide put out by Eaton that covers some of it...

http://downloads.eatoncanada.ca/dow.../SA08302002E - Control Panel Design Guide.pdf

See pages 16 and 26.

 

[don_resqcapt19]

Don,
Then is there a standard that can be referred to regarding control wiring?
NFPA 79 appears to be a well kept secret as I have found many that have never scene a copy of it or even know that bit exists.
I worked for a large MCC manufacturer and I agree on the color code that you had referred to, red being the basic bucket control circuit, yellow for separate control provided external to the bucked, and blue for DC. A yellow warning label was applied to the door warning of separate control.
Dave

Dave,
If the control wiring is external and covered by the NEC, I don't think there are any rules that specify the colors that are to be used for that wiring.