Favorite Material for Outdoor Panel Mounting - Page 1
Forum section: electronics / projects

author: akimbojimbo
author_rank: Contributor
timestamp: July 11, 2022, 04:43:57 am
content: Hello y'all,I'm curious what everyone's favorite base plate is when it comes to mounting electrical panels in outdoor environments (meters, service disconnect, ATS, etc). I've long heard that mounting direct to siding is less than ideal as the layered style of siding creates areas for moisture to sit and create corrosion. So what flat material are you experts mounting your panels to?I know a common one in my industry is pressure treated plywood, which is fugly in my opinion. I'm more inclined to an engineered plastic, but I'd like to know what the people that do this everyday prefer.Thanks!

author: ajb
author_rank: Super Contributor
timestamp: July 11, 2022, 11:27:50 pm
content: Not sure how many folks here do this sort of thing that often. The kind of equipment you're talking about is more the territory of electricians than electrical engineers.I think a lot of this depends on how much equipment you're dealing with and where it's getting installed.If you're just concerned about trapped moisture behind the equipment, then you don't necessarily need a mounting panel--just some standoffs to create an airgap between the equ and the siding.I've been using cellular PVC trim boards for smaller outdoor mounting (receptacle boxes, hose bibs, etc) and they work nicely--easy to machine with woodworking tools and don't need paint--and there are similar materials available in up to 4'x8' sheets. However I wouldn't necessarily trust a couple of screws into it to hold up a big heavy ATS or whatever. Maybe if you predrill mounting holes and install tee nuts or something?I think plywood is probably the best bet for a panel that needs to provide structural support. Painting it will help with the fugliness, just use a good quality outdoor paint. Or you could cover it with a plastic trim sheet.Other kinds of plastic materials could be adequate, but make sure you find something suitable for continuous UV exposure, and you'll probably need to switch fasteners. At the thickness you'd need to get decent rigidity and screw holding sheets of suitable plastic tend to get pretty expensive (though maybe less so compared to current lumber prices?).Another interesting possible material is something like Dibond, which is a plastic sheet with aluminum skin bonded to both sides. It's commonly used for signs. It's typically a few mm thick, so tek screws should work nicely and hold pretty well in the aluminum layers. I'm not sure what the cost is like.

author: Bud
author_rank: Super Contributor
timestamp: July 12, 2022, 12:27:44 am
content: i would not paint plywood but rather stain with a wood preservative product. It looks good and protects from bugs.

author: Gregg
author_rank: Super Contributor
timestamp: July 12, 2022, 12:46:11 am
content: The best practice is to use strut vertically so that moisture cannot build up between the siding and the electrical enclosure. There are many sizes, shapes and materials as well as brackets / fasteners.

author: wizard69
author_rank: Super Contributor
timestamp: July 12, 2022, 05:33:11 am
content: Unless you can get a really good seal, mounting to a flat surface would trap moisture and thus lead to corrosion. Your best bet is to elevate off the surface with strut of other mounting hardware. You also need to consider how the local electrical code is set up, there could be requirements for fire resistant materials or who knows what.Beyond all that you don't want to mount directly to siding because in most cases it has zero structural capability.

author: Gyro
author_rank: Super Contributor
timestamp: July 12, 2022, 09:07:06 am
content: I know that thick Paxoline panels are used for things like the cable entry base plates of high power switchgear cabinets. It must be reasonably water resistant to be used in that position but I've no idea about its UV resistance.

author: akimbojimbo
author_rank: Contributor
timestamp: July 14, 2022, 12:43:34 am
content: Thank you all for the considered discourse! I hadn't considered unistrut embarrassingly 🤦 but makes perfect sense to me. I fall in this strange category of emergency power generation where I have no training, company doesn't like to follow OSHA much less NEC so common things to electricians are unknown to me. I enjoy this community but do feel a tad out of place as my work is split 50/50 between things like 4160v 3MW power distribution, and microcontrollers and control systems. Thank y'all for having me!