Author: derek
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How To Curve Trace Through Rapid Shutdown
The general understanding in the solar industry is that it’s impossible to curve trace through module-level rapid shutdown devices, but with the right equipment, it’s 100% possible.
For this video, I used an APsystems RSD-Start kit for APsmart rapid shutdown devices (not in stock anywhere I could find), and a Fluke SMFT-1000, but you aren’t limited to using these tools to accomplish your task. Any curve tracer should work, as long as you use an appropriate transmitter box to turn on the RSDs first.
If you want to build your own (affiliate links ahoy), here’s a general shopping list:
- APsystems Transmitter-PLC with single core
- Capacitor
- Battery bank
- Box-attachable DC socket
- PVC box with DIN rail and cable glands
- An interesting option if you want box-mounted connectors. Be aware that these are probably not technically compatible with MC4, but it’ll work for this purpose.
- Tigo transmitter, if you want to make this for Tigo instead
If you want to make the box for a generically rated Sunspec system, I’d honestly just try sticking with the APsystems transmitter, it’ll probably work.
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Why no SolarEdge or Enphase? – The 3741 Reference
We’ll sometimes get the question, “Can I use Enphase with UL 3741,” or “why isn’t SolarEdge listed on your website?”
They are perfectly good questions — SolarEdge themselves have touted being the first to UL 3741 compliance, since they were listed via Intertek in 2021, and Enphase got certified by UL around the same time. Just recently in May of 2025, Generac listed their inverter to UL 3741 compliance through Intertek. So why aren’t these inverters or systems listed on the website?
