Look at the portion of the 10 conduit runs in the circle. The only way to spin on those elbows is to do so before they're installed in the box. You would then need to lift up the length of RMC with the elbows attached and drop them in to the KO in the box. I'm not saying that is cannot be done but that could be very labor intensive and far more expensive then just using 10-Ericksons at one side of the elbows.
That's certainly not the only way. For example, you can hang the horizontal lengths, spin them onto the elbows, then spin the vertical sections onto the elbows, then tighten the lock-nuts and the strut straps.
I'm not saying that you couldn't do it but at 10 pounds a foot it's not worth the effort to save the cost of an Erickson. You would need to prop up the horizontal runs while the straps are loose and then go back and try to space the conduits correctly while tightening all of these straps back up. Not to mention the difficulty of trying to spin 30'-40' of 4".
Ok. Why not field bend??
They still need to be spun together.
But why wouldn't you just take a 10-ft stick and bend that so the 90 is at the corner then I assume you would have a couple feet to the left and a couple feet to the right that would be straight and you could spin those pieces on. But I assume you would have to lay it out so it works that way
