Solar, PVC, EMT and Corrosion

 

You have to use the right equipment for the job that is suitable for the environmental conditions that it will be installed in.

With electrical equipment you have many options that are perfect for the job that you are doing. On the other hand, you have unlimited options for equipment that will get the job done, but will not last long enough to get your money out of it.

I’ve installed a lot of solar in many different environmental conditions. The main thing to keep in mind when doing electrical work is that cheap is almost never the way to go. Sure, it will work! But most likely you will be right back out to do maintenance on the equipment you just installed a short time ago, and you will have very unhappy customers.

Some companies will think that it is job security to install the cheaper equipment. They often can under bid their competition by using cheaper equipment also. I personally will not work for any company who uses this type of philosophy, nor will I do that on my own projects around the house.

I work with electricians who think that using PVC conduit instead of EMT conduit is somehow cheap or substandard. This simply is not true; they both have a place. PVC isn’t just for underground either. Now I’m not saying that using PVC all over the outside of buildings is good either. Like I said at the beginning you need to use the right products for the location that they are being installed.

For example, in salty environments EMT just does not hold up to the corrosion and will rust out in a years’ time. PVC works great underground but when its installed on the side of a house ran horizontally in direct sunlight it will warp, expand, shrink and all the glued joints will pull apart over time.

So, what do you do if you do need to use PVC on the side of a building because it’s a salty environment and you don’t want to use EMT fearing it will rust out quickly? You just need to install it properly with the knowledge that it is being installed exposed on the outside of a building. One way is running it tight up under the eaves out of the sunlight for horizontal runs and strapping it at no more than 24” intervals.

 

Then when exposed to direct sunlight try to only run it vertically for short distances.  More straps with PVC is usually better in most cases. Painting the PVC conduit after install will also help make it blend in and stops the discoloration from the sun.

 

The main thing is to plan your install so that you have the least amount of exposed conduit possible.

 Unfortunately, when it comes to electrical disconnects and service equipment, corrosion is a big problem. Stainless equipment is expensive and not always an available option.

With combiner boxes and J-boxes they come in all sorts of weather/environment ratings. You can get them made from fiber glass, stainless and PVC. So, make sure you get the right one for the job.