How strong are different sizes of steel electrical conduit?
I would like to build trellises from steel electrical conduit for vine-type garden vegetables (e.g. squashes, melons).
Can someone give me some guidelines on the load-bearing capacity of different sizes of steel electrical conduit?
For example, if I have a six foot span of conduit, how much weight could I expect it to comfortably support and how does this weight change with the diameter of the conduit?
Are there some tables online where I can look up these values? (I tried a Google search but wasn't able to find anything.)
Although some of the plants I'd like to grow are fairly lightweight (e.g. green beans) so load-bearing capacity won't likely be an issue, some others (e.g. watermelons) can produce fruits that weigh 30 pounds apiece. With the possibility of having a number of fruits at once being supported by a single trellis, this could be an issue.
My goal is to figure out the right size of conduit to use - something that's definitely strong enough (e.g. including a margin of error) - but not unnecessarily large as the cost to buy conduit and fittings rises with diameter.
Any useful guidance you could give me on this would be much appreciated.