Advice on mounting an Inverter and MPPT in a small shed

[NorthTown2022]

Looking for advice on type of material to mount solar inverter and mppt's etc.

The interior of my shed is sheeted with 7/16 OSB which likely does not offer much support for.mounting heavy equipment.

I would like to mount to a non flamable material such as cement board or perhaps 1/8" aluminum checker plate but both seem to have thier own draw backs. I would imagine for either i would need to use a 3/4" plywood backer for a bit of integrity.

Wondering what others have used?

 

[lightbulb]

In my shed, all my equipment is mounted to 3/4 inch plywood, attached to the studs.

 

[Ampster]

I used OSB. I also used as many screws as the bracket would take. I do not see the value of a non flammable backer. Most quality inverters have internal fusing so overheating is not a risk.

 

[NorthTown2022]

I used OSB. I also used as many screws as the bracket would take. I do not see the value of a non flammable backer. Most quality inverters have internal fusing so overheating is not a risk.

Using all Victron equipment, a little concerned about heat from the mppt. Read in another post they can get quite hot.

 

[wiseacre]

Using all Victron equipment, a little concerned about heat from the mppt. Read in another post they can get quite hot.

Read in another post someone used spacers so their SCC didn't sit flush on the backing board.

I have a Victron 100/50 mounted flush to plywood. Being over paneled it does get hot when it starts clipping production.
I'll be remounting it soon

 

[Hank Waconda]

Looking for advice on type of material to mount solar inverter and mppt's etc.

The interior of my shed is sheeted with 7/16 OSB which likely does not offer much support for.mounting heavy equipment.

I would like to mount to a non flamable material such as cement board or perhaps 1/8" aluminum checker plate but both seem to have thier own draw backs. I would imagine for either i would need to use a 3/4" plywood backer for a bit of integrity.

Wondering what others have used?

I have plywood mounted to studs with cleats then inverter, SCC's' DC Charger & monitors mounted to to 2nd plywood with reverse cleats so whole system can be lifted up to detach.

 

[Shimmy]

I haven't seen any fire tests to demonstrate it, but I have seen the aftermath of a few electrical fires. I've seen many cases of scortched drywall or wood, but where the equipment was mounted to unistrut there was no actual fire spread. I am curious what is really more effective as a combustible surface vs the intended use of establishing fire spread rates.

 

[wdwtx2.0]

I have mine on 3/4 plywood and 1/2" sheetrock with spacers.

 

[HRTKD]

My only complaint about cement board is that it is dusty. Every hole you drill and fastener you put in adds to the dust.

My two Victron 100/50 are mounted within a few inches of each other, on 3/4" plywood. It's in an RV, so space was limited and adding even 1/4" cement board was questionable. If I do something in a more open environment like a shed, cement board is what I'll probably use.

 

[NorthTown2022]

I haven't seen any fire tests to demonstrate it, but I have seen the aftermath of a few electrical fires. I've seen many cases of scortched drywall or wood, but where the equipment was mounted to unistrut there was no actual fire spread. I am curious what is really more effective as a combustible surface vs the intended use of establishing fire spread rates.

What do you mean by intended use of establishing fire spread rates?

 

[NorthTown2022]

If I do something in a more open environment like a shed, cement board is what I'll probably use.

This is the direction I'm leaning towards at this time as well, with a 3/4" plywood backer.

 

[venquessa]

Read in another post someone used spacers so their SCC didn't sit flush on the backing board.

I have a Victron 100/50 mounted flush to plywood. Being over paneled it does get hot when it starts clipping production.
I'll be remounting it soon

Yea, I had an MPPT 75/15 with 20A of panels on it. It was right and toasty. Probably 45*C on the surface. So much heat it was actually causing the 10AWG cable AND MCB's to get warm to the touch.

I got another today, so they are each running only one 10A panel each and limited to 8A battery side. They are much cooler now.

I mounted everything to 18mm MDF.

The Victron MPPT 75's have no heat-sinking on the rear and no air path behind it either. Spacers might help, but without heat sink fins airflow will have limited effect.

If you were worried, you could thermal glue a heatsink on.

I expect however, Victron's design is fully away of the heat and is designed to handle it.

 

[BradCagle]

I use cement backer board https://www.homedepot.com/p/James-H...ft-x-5-ft-Cement-Backerboard-220022/100183556

you can use this on top of plywood or OSB.

 

[SilverbackMP]

I used commercial closed cell spray foam as flash and bat, followed by Rockwool (mineral wool) which is fire resistant and fills up the voids, then 3/4 ply, then 5/8 type X dry wall. The spray foam was likely overkill but I was getting my shop done at the same time.

Also put in a 2x4 and OSB framed floor along with spray foam because it was an a slab with no insulation. Put rolled rubber in over that.



Outside is now ag metal.



Retrofit of an old shed that had rotting T1-11 siding and flying squirrels living inside and 25 years of my dad’s accumulation. If it were being done as a separate project, I wouldn’t have done the spray foam. Just house wrap and Rockwool.

All of the walls got plywood as I have sh!t screwed to them all including two swing out short depth server racks for my business and personal use.

 

[Shimmy]

What do you mean by intended use of establishing fire spread rates?

When they talk about "fire rated" materials, they are tested as a wall (or floor or ceiling) assembly to establish a wall fire rating -- 30 minutes, one hour, two hours, etc., where the test is how long it takes the other side of the wall to reach a certain temperature.

Type-X drywall as an example has fiberglass reinforcement internally, rather than just relying on the outisde paper, and it has requirements that it be screwed down at specific intervals and is rated based on the type of studs it is attached to... and what is on the other side. It still has a paper outer coat which can catch fire.

Cement board directly behind equipment only eliminates (again in my minimally-informed opinion) the paper facing of the drywall. When you have regular drywall right next to it then from a fire spread standpoint you really haven't achieved much.

In contrast, placing equipment on metal strut eliminates (ok, technically reduces) the conductive heat transfer from the electrical equipment to the substrate. It can only potentially make the situation worse if it creates a flue for fire to spread vertically. This assumes that the electrical fire is self-limiting; you have fuses or circuit breakers that will interrupt power in a reasonably short time.

The math gets a little different when you start talking about NMC batteries which are not self-extinguishing, or when you talk about making a garage fire worse by mixing a gasoline fire with additional fire load of the batteries.

Again, this comes from my place of understanding about half to 2/3 of the process and having no direct experience with being physically present when electrical equipment mounted on the wall bursts into flame. What I do know is that mounting the equipment in a wood shed with one side having cement board and the roof and other walls of the shed being exposed wood... the cement board isn't going to do much to save you if there is a fire.

 

[NorthTown2022]

I used commercial closed cell spray foam as flash and bat, followed by Rockwool (mineral wool) which is fire resistant and fills up the voids, then 3/4 ply, then 5/8 type X dry wall. The spray foam was likely overkill but I was getting my shop done at the same time.

Also put in a 2x4 and OSB framed floor along with spray foam because it was an a slab with no insulation. Put rolled rubber in over that.

View attachment 151232

Outside is now ag metal.

View attachment 151231

Retrofit of an old shed that had rotting T1-11 siding and flying squirrels living inside and 25 years of my dad’s accumulation. If it were being done as a separate project, I wouldn’t have done the spray foam. Just house wrap and Rockwool.

All of the walls got plywood as I have sh!t screwed to them all including two swing out short depth server racks for my business and personal use.

Nice job. I like Rockwool, used ot myself.

 

[NorthTown2022]

When they talk about "fire rated" materials, they are tested as a wall (or floor or ceiling) assembly to establish a wall fire rating -- 30 minutes, one hour, two hours, etc., where the test is how long it takes the other side of the wall to reach a certain temperature.

Type-X drywall as an example has fiberglass reinforcement internally, rather than just relying on the outisde paper, and it has requirements that it be screwed down at specific intervals and is rated based on the type of studs it is attached to... and what is on the other side. It still has a paper outer coat which can catch fire.

Cement board directly behind equipment only eliminates (again in my minimally-informed opinion) the paper facing of the drywall. When you have regular drywall right next to it then from a fire spread standpoint you really haven't achieved much.

In contrast, placing equipment on metal strut eliminates (ok, technically reduces) the conductive heat transfer from the electrical equipment to the substrate. It can only potentially make the situation worse if it creates a flue for fire to spread vertically. This assumes that the electrical fire is self-limiting; you have fuses or circuit breakers that will interrupt power in a reasonably short time.

The math gets a little different when you start talking about NMC batteries which are not self-extinguishing, or when you talk about making a garage fire worse by mixing a gasoline fire with additional fire load of the batteries.

Again, this comes from my place of understanding about half to 2/3 of the process and having no direct experience with being physically present when electrical equipment mounted on the wall bursts into flame. What I do know is that mounting the equipment in a wood shed with one side having cement board and the roof and other walls of the shed being exposed wood... the cement board isn't going to do much to save you if there is a fire.

Well I sure hope nothing bursts into flames. I was thinking a backer may help prevent that.

I've got an 8" exhaust fan that will certainly act as a flue. Damn now i'm starting to think fire supression! Lol.

Still feeling like a little cement board might be a good idea but i am hearing you.. something to think about for sure