Interesting problem here, I think.
I've got an Enphase PV system backfed into a panel on a 20A 240V breaker. All is good, wired just as recommended.
The Enphase microinverters communicate with their Envoy communications box (which provides internet access to monitor PV system performance) by carrier modulation at around (I understand) 140 kHz, over the building wiring.
Trouble is, I believe, that the client has a number of things that are interfering with that (including, for example, a plug-in intercom system).
It is possible, in principle, to isolate the Enphase system using Ferrite-core chokes to eliminate that interference. Or, alternatively, isolate the noise-producing circuits. However, since the intercom has to be able to communicate _across_ circuits (wherever they plug it in), really the Enphase has to be isolated.
Problem: the microinverters are on a 240V 2-pole breaker, but the Envoy plugs into 120. What this boils down to is: these 240V and 120V circuits need to be isolated from the rest of the panel, but not from each other.
A solution: run a 240V wire out to a subpanel, loop that through a choke, and then split it to a 240 for the inverters and a 120 for the Envoy. Easy peasy.
However, electrically that's EXACTLY the same as adding a 120V outlet off one leg of the 240V breaker in the main panel, and running both legs through a choke before they get to the breaker in the main panel. Since everything is packed in a fairly small closet, the outlet could be right next to the panel, and dedicated to the Envoy. I can't figure out if there are code problems with this.
Thanks for any thoughts.
I've got an Enphase PV system backfed into a panel on a 20A 240V breaker. All is good, wired just as recommended.
The Enphase microinverters communicate with their Envoy communications box (which provides internet access to monitor PV system performance) by carrier modulation at around (I understand) 140 kHz, over the building wiring.
Trouble is, I believe, that the client has a number of things that are interfering with that (including, for example, a plug-in intercom system).
It is possible, in principle, to isolate the Enphase system using Ferrite-core chokes to eliminate that interference. Or, alternatively, isolate the noise-producing circuits. However, since the intercom has to be able to communicate _across_ circuits (wherever they plug it in), really the Enphase has to be isolated.
Problem: the microinverters are on a 240V 2-pole breaker, but the Envoy plugs into 120. What this boils down to is: these 240V and 120V circuits need to be isolated from the rest of the panel, but not from each other.
A solution: run a 240V wire out to a subpanel, loop that through a choke, and then split it to a 240 for the inverters and a 120 for the Envoy. Easy peasy.
However, electrically that's EXACTLY the same as adding a 120V outlet off one leg of the 240V breaker in the main panel, and running both legs through a choke before they get to the breaker in the main panel. Since everything is packed in a fairly small closet, the outlet could be right next to the panel, and dedicated to the Envoy. I can't figure out if there are code problems with this.
Thanks for any thoughts.
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