Non-essential Load Shedding in Main Load Center

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LatentEnergySolutions

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I have an 8kW SolarEdge install for a service company. They want battery backup primarily for their onsite server and furnace. However, they also need to be able to operate their garage doors, and other minor loads, that would be minimal drain on the battery. The only things they don't want to be able to run are automatic high loads like the Air Conditioner (50A) and Hot Water (electric 30A). They need the opposite of a critical loads panel. Isolate the couple of circuits that should NOT be available in backup.

I misunderstood Shunt Breakers and thought they would provide fail-safe disconnect in the event of loss of signal (grid 120V). I bought some and funny thing, they kept tripping when provided 120V. I am looking for something that simple and self contained that will disrupt power to it's circuit when the grid is down.

I have considered using SolarEdge Load Controller to turn off devices during backup, but it seems excessively complicated in operation and equipment for such a simple function. Both circuits would need a matching rated contacter, housing, mounting location, wiring... Maybe I can use the Load Controller to trip the Shunt Breaker?

Is there a more straight forward component? A breaker that has to be manually reset after loss of power?
 
You could install normally open contactors on the loads that you do not want to power with the battery backup and connect a power supply on the line side of the ATS to control the contactors. When the grid goes down the power will switch to the batteries but the contactors will stay open.
 
ggunn said:
You could install normally open contactors on the loads that you do not want to power with the battery backup and connect a power supply on the line side of the ATS to control the contactors. When the grid goes down the power will switch to the batteries but the contactors will stay open.
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That is what I THOUGHT the Shunt Breakers were doing in a nice tidy self contained component.

I will probably go that route. It is just not as tidy. I appreciate your input.
 
LatentEnergySolutions said:
I have an 8kW SolarEdge install for a service company. They want battery backup primarily for their onsite server and furnace. However, they also need to be able to operate their garage doors, and other minor loads, that would be minimal drain on the battery. The only things they don't want to be able to run are automatic high loads like the Air Conditioner (50A) and Hot Water (electric 30A). They need the opposite of a critical loads panel. Isolate the couple of circuits that should NOT be available in backup.

I have considered using SolarEdge Load Controller to turn off devices during backup, but it seems excessively complicated in operation and equipment for such a simple function. Both circuits would need a matching rated contacter, housing, mounting location, wiring... Maybe I can use the Load Controller to trip the Shunt Breaker?

Is there a more straight forward component? A breaker that has to be manually reset after loss of power?
Click to expand...

Why is using Solaredge Load controller viewed as excessively complicated? You will need to add a Solaredge backup interface, and if adding Solaredge batteries you will likely add the Home network wireless card to inverter, so adding one or 2 load controllers that will integrate well with the monitoring and control does not seem complicated to me.
 
LatentEnergySolutions said:
That is what I THOUGHT the Shunt Breakers were doing in a nice tidy self contained component.
Click to expand...

A 'shunt trip' is supposed to trip when you provide 120V to the trip coil.

If you want a breaker that is supposed to trip when 120V is removed from the control coil, you want an undervoltage trip breaker. Same basic idea as a shunt trip.

You might want to think though your plan, however, and use a contactor as the others have described. If you use a UV trip breaker to load shed, you will need manual intervention at the breaker panel every time there is a loss of mains power.

-Jonathan
 
LatentEnergySolutions said:
That is what I THOUGHT the Shunt Breakers were doing in a nice tidy self contained component.

I will probably go that route. It is just not as tidy. I appreciate your input.
Click to expand...
Don't shunt trip breakers need to be manually reset when whatever conditions resulted in their shutting off are resolved? An advantage of the method I spoke of in post #2 is that the contactors will restore the connections when the outage is over. Another strategy that could be better is to use normally closed contactors with their controls driven by a power supply on the inverter circuit so that those circuits would be disconnected when the generator is running.
 
ggunn said:
Don't shunt trip breakers need to be manually reset when whatever conditions resulted in their shutting off are resolved? An advantage of the method I spoke of in post #2 is that the contactors will restore the connections when the outage is over. Another strategy that could be better is to use normally closed contactors with their controls driven by a power supply on the inverter circuit so that those circuits would be disconnected when the generator is running.
Click to expand...
Better for sure
Waste of his expensive shunt trips but Charge them out anyway.
 
ptonsparky said:
Better for sure
Waste of his expensive shunt trips but Charge them out anyway.
Click to expand...
Similarly, we used contactors to shut off some of the microinverters in a PV system with battery backup during outages because of the limit to how much PV can be connected to a PowerWall when it is running off grid.
 
winnie said:
A 'shunt trip' is supposed to trip when you provide 120V to the trip coil.

If you want a breaker that is supposed to trip when 120V is removed from the control coil, you want an undervoltage trip breaker. Same basic idea as a shunt trip.

You might want to think though your plan, however, and use a contactor as the others have described. If you use a UV trip breaker to load shed, you will need manual intervention at the breaker panel every time there is a loss of mains power.

-Jonathan
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Thank you, I will look into Undervoltage Trip Breakers.

In this usage case the need to reset the breakers is not an issue. They lose power rarely and if the circuits were off for longer than necessary, it would only be a minor inconvenience.

As far as other feed back on complexity and cost. Shunt Trip (wrong use) are cheaper and more direct, than the additional Load Controller (which still can't directly disconnect the devices), plus a contactor and housing, and electricians to wire it all in. There are also not any good mounting locations for the housing.

I appreciate all the comments!
 
I don't really understand how the SE load controller works (because I don't use SE these days and don't want to read up) but if it can control a contactor or relay that is probably the best and most straightfoward. I've used contactors with Enphase to control similar loads, and it's worked pretty well so far. The one downside of contactors in residential is the hum they make, which can annoy homeowners in some circumstances. So for 30A and below I use an RIB (by Functional Devices, great brand name) because they have DC relays internally which are quiet. Unfortunately they don't make them for 50A.
 
jaggedben said:
I don't really understand how the SE load controller works (because I don't use SE these days and don't want to read up) but if it can control a contactor or relay that is probably the best and most straightfoward. I've used contactors with Enphase to control similar loads, and it's worked pretty well so far. The one downside of contactors in residential is the hum they make, which can annoy homeowners in some circumstances. So for 30A and below I use an RIB (by Functional Devices, great brand name) because they have DC relays internally which are quiet. Unfortunately they don't make them for 50A.
Click to expand...
I never used a load controller, but did look into them. They use SolarEdge Home Network wireless (probably a proprietary 802.15 protocol like Zigbee) to communicate to the inverter, and looks like they can handle about 4A. They cost about $120 I believe, and they are pretty small. I agree, if installing a SolarEdge PV system with battery backup, they are a very minor cost addition compared to the cost of battery, BUI, etc, and it would seem to me that with the inverter and monitoring system integration, it would be the way to go, and just add the contactor or high power relay needed. The SolarEdge battery also communicates using wireless Home Network protocol, so you need the card in the inverter anyway.
 
solarken said:
I never used a load controller, but did look into them. They use SolarEdge Home Network wireless (probably a proprietary 802.15 protocol like Zigbee) to communicate to the inverter, and looks like they can handle about 4A. They cost about $120 I believe, and they are pretty small. I agree, if installing a SolarEdge PV system with battery backup, they are a very minor cost addition compared to the cost of battery, BUI, etc, and it would seem to me that with the inverter and monitoring system integration, it would be the way to go, and just add the contactor or high power relay needed. The SolarEdge battery also communicates using wireless Home Network protocol, so you need the card in the inverter anyway.
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Fwiw, it sounds dumb to me. Seems very much an afterthought, badly engineered solution. With an Enphase System Controller I get four auxillary contacts to handle 24V Class 1 circuits to control relays, and once the software is setup there's no dependence on anything wireless, no extra parts from the manufacturer. From there I can supply the relays or contactors to handle whatever amps I can design. For SE shouldn't this functionality be built into the BUI? But apparently it's not and I essentially have to spend an extra $480 for the equivalent functionality. And it's zigbee. 🤢 Based on past experience with SE zigbee, and zigbee in general ... no thank you.
 
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