Recommendations for 3-phase “two-tier” surge protection (subpanel + rooftop RTUs)

[MDVoltage]

Hi everyone,
I’m looking for recommendations on a three-phase, two-tier surge protection approach and I’m hoping to get some guidance from those of you who do a lot of SPD work.

Project: Church with rooftop HVAC/RTUs. They had a storm last summer that took out boards and components—roughly $15,000 in damage—so they want to be proactive.

Existing electrical setup / goal:

• There’s a 200A 3-phase HVAC subpanel I’d like to protect (Tier 1 at the subpanel).
• Then add three additional SPDs at the rooftop units (Tier 2 at/near each RTU disconnect or unit feed) to protect the equipment electronics.

I had one recommendation for Transient Protection Design (TPD) equipment, but it’s pretty expensive, and surge protection is a bit of uncharted territory for me beyond the basics. ($5,650 for 4 SPU’s)

What I’m asking the group:

1. Any recommended manufacturers/models for a setup like this (Tier 1 + Tier 2) in 3-phase?
2. Any guidance on Type 1 vs Type 2 choices for the subpanel and what you typically use at the rooftop units/disconnects?
3. Any “must have” specs you look for (kA ratings, SCCR, NEMA enclosure ratings, monitoring contacts, etc.)?
4. Any practical install tips for rooftop placements (weatherproofing, mounting, lead length best practices, coordination between the two tiers)?

Appreciate any suggestions—especially what you’ve used in the real world that holds up well and doesn’t cost a fortune.


Thanks in advance,

Michael
MD Electrical Solutions, LLC