Using wood for a control box.. Smart or Dumb

[RussPDX]

I am not an electrician, but I know enough to be dangerous. Have built a control panel with a basic Stc-1000 for my fermentation chamber and the box was $12 at Lowes.

I am building a Control panel with a PhD from auberins and a 240/40 SSR with a heat sink. . Boxes that will fit the PhD are about $30 so I was thinking about building a semi open designed box for high air flow and using scrap wood that I have here. . Is this safe or dumb? I have some aluminum flashing that I could line the box or at least around do the SSR. Just concerned that the heat sink or SSR could cause a fire.

Thanks

 

[Paps]

Would you build your homes fuse box out of wood?

 

[maierhof]

I did it with a smaller plastic box for the main connections and have the SSR and its heat sink in the wooden box below - dont put the connections too close to the wood of course. Just build it with enough layout room and adequate ventilation...

Use the connectors with covers (bot mine at home depot) to help you make the connections. They make it safer too.

the second photo is of it hanging on my wall for storage

 

[ryane]

In a wood box, what happens in a wire is shorted to the wood? It doesnt blow the breaker, so you have less protection

look on ebay for boxes and dont build your controller in a wood box

Why skimp on spending $30 when its for safety? seems like a no brainer

 

[augiedoggy]

In a wood box, what happens in a wire is shorted to the wood? It doesnt blow the breaker, so you have less protection

look on ebay for boxes and dont build your controller in a wood box

Why skimp on spending $30 when its for safety? seems like a no brainer

and what happens if the bare wire touches the wood?.....nothing at all unless that wire was so hot for some other reason that it burned the wood.. but you wont be electrocuted by the non conductive wood.
In a metal box it can arch out and electrify the panel if its not grounded properly.... Theres a lot of ifs involved and I would still suggest using a metal or plastic box myself...

That said this is not a 100 amp electrical box and its ultimately protaected by an external breakered line powering it unlike the main service box(which is mounted on a wooden wall in most cases), its an appliance, and they made tv's and radios in wooden cabinets for many years and they apparently werent all that dangerous...My advice is if you do use wood, mount everything that generates any heat to a metal plate on standoffs to prevent direct contact with the wood at least...

 

[augiedoggy]

I did it with a smaller plastic box for the main connections and have the SSR and its heat sink in the wooden box below - dont put the connections too close to the wood of course. Just build it with enough layout room and adequate ventilation...

Use the connectors with covers (bot mine at home depot) to help you make the connections. They make it safer too.

the second photo is of it hanging on my wall for storage

Not trying to give you a hard time but You realize you put the hottest, most dangerous and likely to burn up components of the build in the worst possible place right?

 

[flars]

Electronics have been buried in high end wood cases for many years. An oil finish may be better than a french polish for the environment of your control panel.

 

[RussPDX]

My thinking was along the lines of Auggies. That the danger really comes from the heat of the SSR potentially igniting the wood. I just don't have a sense of how hot it will get. Other than flashpoint there really is no difference that I can see between using wood and a plastic box. As was previously mentioned I would think that using a metal box would be even more dangerous especially if the box was not properly grounded. I spoke to our lead R&D guy at work today who while not an electrical engineer does have quiet a bit of electrical experience and he was in agreement that there really was no electrocution issue especially since I am wiring the box into a gfci but to make sure that I have plenty of ventilation for the heat. Since it will not be used unattended any issues should be easily noticed pretty quickly.

Thanks for all the feedback.


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[trimixdiver1]

My thinking was along the lines of Auggies. That the danger really comes from the heat of the SSR potentially igniting the wood. I just don't have a sense of how hot it will get. Other than flashpoint there really is no difference that I can see between using wood and a plastic box. As was previously mentioned I would think that using a metal box would be even more dangerous especially if the box was not properly grounded. I spoke to our lead R&D guy at work today who while not an electrical engineer does have quiet a bit of electrical experience and he was in agreement that there really was no electrocution issue especially since I am wiring the box into a gfci but to make sure that I have plenty of ventilation for the heat. Since it will not be used unattended any issues should be easily noticed pretty quickly.

Thanks for all the feedback.


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The difference is that wood isn't rated for this. Burn your house down or hurt someone and the insurance company will run the other way. Don't do it, it's not the 40's. We have UL approval for a reason.


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[maierhof]

Not trying to give you a hard time but You realize you put the hottest, most dangerous and likely to burn up components of the build in the worst possible place right?

What you don't know is that this was my first control panel and money was tight to say the least. i had the extra wood so i just made it. i only run 110v right now and have a 50amp ssr with the correct heatsink to match it when i do move up to 240v. This of course will also be about the same time that i will expand my system and build a rig and therefore a new box so... I fully understand the risks and don't have a problem with them. I am also behind a GFCI breaker too for extra comfort. If it starts a fire - I can just unplug it or take 8 extra steps to the breaker itself.

Feel better?

 

[trimixdiver1]

What you don't know is that this was my first control panel and money was tight to say the least. i had the extra wood so i just made it. i only run 110v right now and have a 50amp ssr with the correct heatsink to match it when i do move up to 240v. This of course will also be about the same time that i will expand my system and build a rig and therefore a new box so... I fully understand the risks and don't have a problem with them. I am also behind a GFCI breaker too for extra comfort. If it starts a fire - I can just unplug it or take 8 extra steps to the breaker itself.



Feel better?

The subject of this thread is whether it's smart or dumb to use wood as a enclosure. It's dumb, no ifs ands or buts about it, justify it as much as you want, it's still a foolish thing to do. If you don't have the money than don't do it. Home brewing is a hobby. Save up and do it right

 

[user 163849]

No worries. It looks fine to me. There is nothing in that box that will come even close to getting hot enough to ignite that plywood.

 

[trimixdiver1]

No worries. It looks fine to me. There is nothing in that box that will come even close to getting hot enough to ignite that plywood.

How do you know? How about at failure? In an ideal world with gumdrop trees and butterscotch roads yes it would be ok. In the real world we plan for the worst and do our best to keep it contained.

 

[user 163849]

How do you know? How about at failure? In an ideal world with gumdrop trees and butterscotch roads yes it would be ok. In the real world we plan for the worst and do our best to keep it contained.

Well, I reckon I do not know. But based on personal experience I am confident enough that I would not assume that box will go up in flames any sooner than I would that you will be struck by lightning while riding a unicycle on the deck of that submarine at the bottom of the sea.

Not sure what the ideal world statment is all about. But in my ideal world the trees would be made of potential firewood and roads would be few and far between. If you were trying to imply that I do not know what I am talking about you are mistaken.

You do realize that nuke plants and submarine life are not "real world" for most of us? Your safety standards are high and there is nothing wrong with that. In the "real world" where the rest of us live it is not unusual to temper industrial strength safety standards with a good dose of common sense. Budget is a bit more of a concern for those of us who have to sweat for a living than it appears to be for nuclear guru such as yourself. Hell, some of us "cheapasses" (as you put it) are retired and on an even tighter budget.

In my 65 years I have done many things that you would consider stupid, deadly, and likely to burn my house down. I'm still here as is my house.

 

[BlkWater_brewer]

I really don't understand the issue on this post. Of course you can build your control box out of wood or anything else you want. If you wire it cleanly enough - use plexiglass for a different look. Wood is easy to cut for PID's and other components, little chance of a fire from a SSR especially if mounted to a heat sink same goes for power plugs. Use a wood box with a metal face panel if you want. To me, it's not the $$ it's more using what you have, be creative. If you are building a control box for commercial size vessels I'd say no, but for home brew size equipment -5 to 20 gallons do what you want. You might miss out on the "cool factor", but are you building this to brew with or to look at? Everyone is correct when they say electricity is nothing to play with, use care and common sense and you'll be fine.

 

[augiedoggy]

Yes I understand whats being said myself and am all for not spending where its not needed but...

you can make the panel out of wood, you can also skip the gfci protection. you can even use connectors that are rated for less amps than your pushing through them and not have an issue...But the bottom line this increases your risk to danger, maybe not a lot but it cost $33 for a 12x12x6 plastic enclosure. The pics of the panel above show the smaller $22 plastic enclosure mounted to a wooded box..and the stuff that should be in the plastic box the most is on the wood . Thats why I pointed it out. $11 more and it would have been worth it for piece of mind. there is a reason to will not find a single ul listed of nema wooden project/ electrical enclosure..nor would any electrician or insurance company accept that this was a safe design in todays day and age. They would never meet code as they are an unnecessary danger especially when dealing with 220v and components that generate heat and have a tendency to melt and even catch on fire when they fail. there are threads here where people have reported that this has happened...

Also, if someone cant afford or is too frugal or cheap to buy a $33 nema enclosure they are certainly more likely to skimp on or components of the built like the type of ssr used... I myself have been using the knock off fake fotek ssrs from amazon and ebay (over 90% of them are fakes on there btw) and these do have the highest failure rate according to the theads and failures reported here..they dont even have the correctly rated components inside of them to handle the loads they state on the stickers in some cases.
So far I have had no issues but mine are in a plastic box with heatsinks and fans to keep things cool.
I do believe it can be done and be fairly safe but that likely require more effort than just using a plastic,metal or fiberglass enclosure since you would need metal plates and standoffs and such. So honestly if we were talking about a fancy wooden cabinet (with said precautions) my opinion would be go for it if you really want to but to just throw everything in a plywood box or crate to save a couple bucks I just dont think its a good idea or worth the extra risk and hassle thats sure to follow if there was an incident but hey thats just my opinion. (and apparently the opinion of all the people writing the electrical safety codes for such devices.) I am usually the one on the opposite end of this argument but I'm at least defending the use of something that is rated for the use Im using it for like fuses instead of fancy din rails of breakers or smaller gauge wire for smaller amp circuits...

 

[maierhof]

... The pics of the panel above show the smaller $22 plastic enclosure mounted to a wooded box..and the stuff that should be in the plastic box the most is on the wood . Thats why I pointed it out.

Also, if someone cant afford or is too frugal or cheap to buy a $33 nema enclosure they are certainly more likely to skimp on or components of the built like the type of ssr used... I myself have been using the knock off fake fotek ssrs from amazon and ebay (over 90% of them are fakes on there btw) and these do have the highest failure rate according to the theads and failures reported here..they dont even have the correctly rated components inside of them to handle the loads they state on the stickers...

...So honestly if we were talking about a fancy wooden cabinet (with said precautions) my opinion would be go for it if you really want to but to just throw everything in a plywood box or crate to save a couple bucks I just dont think its a good idea or worth the extra risk and hassle thats sure to follow...

Ok - duly noted then - you will be the first one I pm if it starts a fire then... =;>

Just as a follow then here are a few more pis for ya then...

 

[maierhof]

Take a look

View attachment 1417459918452.jpg

View attachment 1417459936492.jpg

 

[LandoLincoln]

The difference is that wood isn't rated for this. Burn your house down or hurt someone and the insurance company will run the other way. Don't do it, it's not the 40's. We have UL approval for a reason.

No one cares about my iPad

I didn't get my control panel UL listed. Did you?

 

[trimixdiver1]

It's all good, Darwin would approve. And we do need examples to show those that do want to do it right and safely. So post plenty of pics, we will not say: I told you so.

 

[user 163849]

I just ran a little experiment out in my workshop. I heated a plastic junction box similar to what is being recommended here. It was sitting on a small piece of plywood and I direced the hot air from a heat gun where the two met. The plastic began to flow at around 410 degrees Fahrenheit. Though blackened a bit the plwood never showed signs of smoldering. Perhaps it proves nothing but it was fun.

 

[user 163849]

Pic

 

[user 163849]

The setup

 

[flars]

I just ran a little experiment out in my workshop. I heated a plastic junction box similar to what is being recommended here. It was sitting on a small piece of plywood and I direced the hot air from a heat gun where the two met. The plastic began to flow at around 410 degrees Fahrenheit. Though blackened a bit the plwood never showed signs of smoldering. Perhaps it proves nothing but it was fun.

I was thinking along the same line. Have the nay sayers measured the internal temperature of there control box during operation, for a temperature high enough to ignite the plywood.

 

[b-boy]

My Dad is a Chemical engineer. He specializes in copper, and specifically in house wiring.

His company did some controlled experiments concerning electricity and house fires a few years back. The outcome of the experiments indicated that it was very, very difficult to catch a solid piece of wood on fire with an electrical short. Generally, when a fire starts it's the dust or debris within the wall that ignites, not the framing lumber.

That being said, I still wouldn't use wood.

 

[augiedoggy]

Sh!t happens.. better to spend the extra $10 and not worry about it is all im saying...I believe that plastic used in electrical boxes will melt first but the wood is more likely to catch fire unless im mistaken... but yes metal would be an even safer choice to prevent issues. (As the guy in the first link found out but we dont know what kind of shortcuts he took or components used)

http://moorepage.net/hottub2.html

http://www.biopowered.co.uk/wiki/Solid_state_relay_(SSR)

 

[z-bob]

The difference is that wood isn't rated for this. Burn your house down or hurt someone and the insurance company will run the other way. Don't do it, it's not the 40's. We have UL approval for a reason.

The controller isn't going to be UL listed anyway.

This isn't going to be buried in an attic or behind a wall during operation. So what exactly is the danger? Just that it presumably would never pass muster in a mine or chemical plant?

 

[trimixdiver1]

The controller isn't going to be UL listed anyway.



This isn't going to be buried in an attic or behind a wall during operation. So what exactly is the danger? Just that it presumably would never pass muster in a mine or chemical plant?

Or with anyone who sees it and knows what they are looking at. It's embarrassing.

 

[user 163849]

Or with anyone who sees it and knows what they are looking at. It's embarrassing.

So it doesn't meet your standards. No problem, there is no need, reason nor desire to do so. It really is that simple.

 

[RussPDX]

Thank you everyone for your feedback. It is an interesting topic to say the least. Other than, because it is code, or that's how it's done, there really does not seem to me to be inherent danger in using a non metal box. That is to say, if proper connectors, wires, GFCI and whatnot are used, but that is assumed true as my original post was specific to the box itself. Really as far as I can tell, if you are using it fully supervised (not setting and forgetting) I don't see how you are creating an unsafe environment. Maybe if you put it in a pile of dry leaves.....

There is no added risk of shock from wood, so really fire is the reason and components would start to smoke and such before the box would ignite and again, if it is operated fully attended then I would not be too worried about that. Of course there will be those that disagree and those that do agree, but that is why we are here, to have an open forum to discuss and in the end we have to make our own decisions.

The best reason I have heard so far for a UL box is that the insurance company will not like other materials....that is extremely valid. I wonder if the insurance company would like that I built the controller myself anyway. I plan on calling them to ask about this when I have a minute and will report back.