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Device to control 480V circuit?


sandpiper

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Not enuf detail ...

 

You want to control 480 volts at what amperage ... but how: on/off or dimmer?

What control voltage will you have available: only 480 volts AC 60Hz or do you have 120V 60Hz AC?

 

What about an 120 volt 60Hz Insteon on/off module powering a 120 volt relay rated for 480 volts?

 

I don't believe there is any Insteon product that can handle that voltage directly.

Edited by Broyd
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That's not according to code. All phases of a 480 volt line must be interrupted concurrently. A TPST relay is required. (A TPDT relay can be used if it's more readily available and/or less costly.) Such a relay with a 120 volt coil is easily controlled with an Insteon device.

 

Edit: changed no. of poles

Edited by stusviews
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You started with 480v and then stated 120v or 277v. Which is it?

 

You also haven't stated what type of load you want to switch and that is important. The unit referenced by Apostolakisl will work fine for 120 and 277 volt incandescent lighting loads but not for motor loads. It should work fine for 240 volt resistive loads also.

 

Motor starting inrush current as well as counterEMF voltages, when turning it off, will likely burn the unit out very quickly.

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That's not according to code. Both phases of a 480 volt line must be interrupted concurrently. A DPST relay is required. (A DPDT relay can be used if it's more readily available and/or less costly.) Such a relay with a 120 volt coil is easily controlled with an Insteon device.

 

I would think that listing 277v means he is powering a single phase 277 device off of a 480v 3 phase wye service, not a 480v device and only interrupting one leg of it.

 

The part about the load being inductive or resistive is good.  Do they make 277v single phase motors though?  Seems like anyone with 277v/480v available would want to take advantage of 3 phase since it would be better and cheaper.

 

But we are making lots of assumptions here.  Would be good to know the truth.

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Thanks for all your thoughts. I have 10 (maybe 12?) 400W HID lamps on that circuit. No motors of any kind. My maintenance guy tells me they are on 480V. I have quite a bit of experience in household stuff, 120/240 Volt, but everything bigger than that is beyond me. So I don't even know whether it is one hot wire with 480 Volts or maybe 2 wires with 277 - but he knows and he will find the proper relay.  I'm not gonna touch it myself.

 

The message I needed was: There is no insteon device, so we have to find a relay and control that by something from insteon.

 

Thank you all!

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Thanks for all your thoughts. I have 10 (maybe 12?) 400W HID lamps on that circuit. No motors of any kind. My maintenance guy tells me they are on 480V. I have quite a bit of experience in household stuff, 120/240 Volt, but everything bigger than that is beyond me. So I don't even know whether it is one hot wire with 480 Volts or maybe 2 wires with 277 - but he knows and he will find the proper relay.  I'm not gonna touch it myself.

 

The message I needed was: There is no insteon device, so we have to find a relay and control that by something from insteon.

 

Thank you all!

You are probably wrong to say what you just said.

 

If your maintenance guy says you are on "480v" he probably means you are on 480v three phase.  This means you have 3 phases of 277v.  Cross two of those phases and you get 480v.  Cross one phase to neutral you get 277v.  If the lamps run on a single phase of the 480 service then the switch I listed above is specifically made for that.

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@stu: It is a commercial building, constructed with growth in mind. The power supply is vastly oversized for what we are using now.

 

I know we have 277V, because most of our machinery and most of our lighting runs on that. But Maintenance Man said these lights are on 480V and added, he has never seen that before - so I am pretty positive they are running on 1 phase 480V. If they were on 2 phases of 277V, he would've said so. But I'll verify that on Tuesday.

We will go with the suggested relay. Thanks, guys! Enjoy the long weekend!

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A bit of research revealed the the lights are powered using a 480 volt LED driver. The driver is powered from standard 110/120VAC or 220/240VAC line power. That's what you need to determine. You do not need to control the 480 volts.

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If the lights pull 480 then they are using two phases of the three to get that. You would then need a relay. I have never heard of single phase 480.

"Off the 480v" is not specific and usually refers to the system only. I have never heard of lighting connected to two phases.

Step down transformers are sometimes connected phase to phase and the secondary 120vac runs the lights.

 

In Canada, many commercial and industrial buildings run 600v lighting but this only means "system" The lighting is always connected to neutral = 360 vac. This way single pole switches on the wall are required and only one pole breakers are used for each circuit. Electricians are required to change light bulbs.

 

Older buildings were run on 600v 3 phase 3 wire and then phase to phase loads were all that were available. Step down transformers were always used for lighting running at 120vac. In later years, once the Engineers were under control, 3 phase 4 wire system were introduced to accommodate 360v lighting and the 3 phase 3 wire system are being phased (pun intended) out. :)

 

The 3 phase , 3 wire systems were floating to ground, and one customer could cause a shared transformer neighbour's equipment to burst into flames when they weren't even there. It takes two to tango. Who ya'  gonna' call? :)

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