@jraef Thanks for a thoughtful post.
So I understand your post, but what about when the external devices are already UL approved. For example no isolation is required when powering a 120 VAC UL approved motor through a mechanical relay - it is as if the motor was plugged into the wall, which it...
Show how part of my question got cut off, here it is in full:
I’m looking at a project to make a electronic tranformer for use within a product, and driving its teathered external devices for a control system. I want to make the output AC voltage configurable between 24VAC and 120VAC. This can...
I’d like to get UL approval on the device. Electronic transformers typically empoly a small transformer for isolation (smaller than typical transformer due to high freq operation). However in this application where 120VAC is an output option, the transformer would be 1:1… and thus be seemingly...
I have a concrete wall in a heating only climate that is insulated from the outside, insulated from the ground, and sits on a percolation barrier. The question is does the wood that contacts the concrete need to be treated?
Reasons (i can think of) wood touching concrete should be treated:
1...
I'm looking at trying to get a 4" duct through a 4x10 doug fir joist. The IRC only "allows" a hole up to 1/3 the height of the joist, however having looked at the guidelines for TJIs, it makes sense to me that solid lumber should be similar: larger holes should be potentially acceptable the...
If the rock lies on the footing, you are right it will rest upon 4" of high density geofoam. The rock weight would be restrained to below the 1% creep limit. But yes I would settle about 0.04". Question is, if we put it on its own footing, would we expect the soil settling to be tremendously...
Hi,
I've got a project with rock siding on the foundation. Half of the basement is exposed, and half in mostly below grade. The exposed section will have rock siding all the way to the footing. We are trying to decide if for the unexposed sections we can compact the soil in lifts and create a...
