Joseph1970
Member
- Location
- Ohio
- Occupation
- Electrician
I have a square d 480 volt starter with 480 volt coil how do I wire this up with a start stop button
Square D 480 volt starter with 480 coil
- Thread starter Joseph1970
- Start date
LarryFine
Master Electrician Electric Contractor Richmond VA
- Location
- Henrico County, VA
- Occupation
- Electrical Contractor
ptonsparky
Tom
- Occupation
- EC - retired
Did you make it?
LarryFine
Master Electrician Electric Contractor Richmond VA
- Location
- Henrico County, VA
- Occupation
- Electrical Contractor
No, just found it with a quick Google image search, like I do most images I post.
TwoBlocked
Senior Member
- Location
- Bradford County, PA
- Occupation
- Industrial Electrician
Might not be required, but I'd like to see fuses on the control wiring.
ptonsparky
Tom
- Occupation
- EC - retired
A couple class CC fuses do save a lot of damage when the coil reaches EOL.
- Location
- Illinois
- Occupation
- retired electrician
Table 430.72(B)(2) shows the requires protection for control circuits tapped off of the motor power circuit, but permits a motor power circuit with a branch circuit OCPD of 45 amps to protect a 14 AWG control circuit.
- Location
- San Francisco Bay Area, CA, USA
- Occupation
- Electrical Engineer
I doubt that diagram was intended to be a full engineering document. As I recall, the source was from some pages describing how motor controls function.
David Castor
Senior Member
- Location
- Washington, USA
- Occupation
- Electrical Engineer
Assuming this is a real device and not a test question: Make sure you buy 600 V pushbuttons. While 480 V control is perfectly legal per the NEC, I'd strongly advise replacing the 480 V coil with a 120 V coil and installing a control power transformer. Running 480 V pushbuttons and switches is an idea whose time has passed.
ptonsparky
Tom
- Occupation
- EC - retired
Stand alone Pump Panels come standard with line voltage controls. Fusing will vary with supplier.
kwired
Electron manager
- Location
- NE Nebraska
Depends on contactor/coil design.
Two most common types of pump panels I run into on irrigation are Square D and Siemens. Square D coils are usually easy to replace. Siemens almost always swell up and you have a hard time taking it apart to replace the coil. Even if the Square D does swell up, it is just designed differently and easier to gain access to deal with the issue.
ptonsparky
Tom
- Occupation
- EC - retired
Too many times I've seen it take PB and/or overload contacts along with it.
- Location
- Tennessee NEC:2017
- Occupation
- Semi-Retired Electrician
I didn't see where the OP said this was for a pump motor.
ptonsparky
Tom
- Occupation
- EC - retired
It doesn't. We diverged a bit with discussion of control fusing but don't think PPs are only used for pumps in the real world.
David Castor
Senior Member
- Location
- Washington, USA
- Occupation
- Electrical Engineer
I think NEMA MCCs still have line voltage control as the minimum standard. It doesn't mean you can't spec something better and safer.
kwired
Electron manager
- Location
- NE Nebraska
Did you mean combination starters?
Don't most MCCs have a control transformer in every bucket usually either 120 or 24 VAC for control voltage?
- Location
- Illinois
- Occupation
- retired electrician
I believe you can order the MCC with line voltage control circuits if you want to....have not seen that in decades.
kwired
Electron manager
- Location
- NE Nebraska
I can't imagine there being much demand for 480 volt control circuits with an MCC.
The larger the MCC the less it might be desired, unless maybe every single motor were very related to one another in a particular process/sub process of the facility.
I can see 120 volt contactor coils being more desirable to be installed if the MCC were supplied by 208/120 and each supplied by line voltage rather than via control transformers though.
- Location
- Illinois
- Occupation
- retired electrician
There is not.
The only time I have seen it in the past 20 years or so, was only for the coil on size 4 and 5 starters, but even there there was an interposing relay and 120 volt CPT and control circuit. The coils for larger starters will require a much larger CPT if the coil voltage is 120 and the use of a 480 volt coil solves that issue.
The last time I saw an actual 480 volt control circuit was in the 70s at an old industrial plant.
kwired
Electron manager
- Location
- NE Nebraska
You still talking about MCC's I assume.
Pump panels we normally use here for irrigation wells, and sometimes other applications as most suppliers sell them for much less than they do combination starters, almost always have 480 volt coils. Siemens is the one that normally has dual volt 240/480 volt contactor coils, Square D and Allen Bradley are the other most popular and only have single voltage coils, 480 volts being the ones that are typically in stock.
The coils for larger starters will require a much larger CPT if the coil voltage is 120. I can understand that aspect.
NEMA contactors in general need larger source to power them. Last summer I solved an issue that an irrigation dealer couldn't figure out. That particular brand of irrigation system has always used the grounded conductor as a safety loop in their control scheme where most others use the ungrounded conductor for the same function. It must pass through every section of the center pivot system and back to the main control contactor at the pivot point and is basically what shuts the system down if it gets stuck, is out of alignment, or any other limits are reached. They had replaced the original contactors (forward and a reverse contactor) in the main control panel that were (likely based on experience) a four pole GE DP contactor with Schneider's much more compact IEC contactors along with some other work. They could not get the system to shut down with a wireless control device they installed that integrates with an app for owner's cell phones to control the system. This device goes near the far end of system because it has GPS capability to tell the app where in the circle the system is oriented and shuts system down by momentarily opening that existing "safety loop". The problem ended up being those new contactor coils draw so much less current that the capacitance in that long loop allowed enough current to keep them held in when they tried to open the circuit. The stop control on main panel still worked as it interrupts the ungrounded conductor. I added a light bulb across contactor coil while their guy was there with me, and tried to explain what was going on, don't know if he understood or not but he saw it worked. I told him he needed more load and it would draw enough to drop the voltage enough to allow the coil to drop out. Not sure what he ended up using. Incandescent light bulb I had was just something I had in truck at the time and was on a temp socket, not really the best thing to leave as something permanent.