malachi constant
Senior Member
- Location
- Minneapolis
I have a situation where multiple chillers arrived on site with a lower SCCR (5kAIC) than specified (65kAIC). Manufacturer/vendor is taking responsibility for it but they need me to engineer a solution that they will pay for. Current-limiting fusing doesn't resolve the situation so looking at an isolation transformer. I'm learning about these for the first time. I am told standard xfmr impedance is 6%, but custom are available up to 10%. Assuming this is the direction we go a custom transformer will work. What effect will this have on a utility bill - I had assumed inefficiency/losses associated the transformer, but will there also be potential power factor issues? Building is a typical mid-sized K-12.
For another option I am trying to find a contractor - one with a UL shop - with capability of taking the control panel back to their shop and rebuilding it as required to list it at the appropriate SCCR. We had a contractor do something like that ten years ago - I was hoping that was the first and only time I would face this issue, but here we are - and think that may be the more palatable solution here. Am I correct in thinking that this is an option? This project is in a different market (Chicago area) than the previous one so am struggling to find the right contractor.
I'm also chasing some leads on "current limiting reactors", which is an unknown thing for me - not expecting that to pan out but I'm desperate enough to be making the calls. For context we're looking at 208V systems with available ISC between 15-35k on 400A-1000A equipment. I'm not looking for someone to engineer it for me, but general thoughts on pros/cons/feasability of solutions are appreciated. Thanks!
For another option I am trying to find a contractor - one with a UL shop - with capability of taking the control panel back to their shop and rebuilding it as required to list it at the appropriate SCCR. We had a contractor do something like that ten years ago - I was hoping that was the first and only time I would face this issue, but here we are - and think that may be the more palatable solution here. Am I correct in thinking that this is an option? This project is in a different market (Chicago area) than the previous one so am struggling to find the right contractor.
I'm also chasing some leads on "current limiting reactors", which is an unknown thing for me - not expecting that to pan out but I'm desperate enough to be making the calls. For context we're looking at 208V systems with available ISC between 15-35k on 400A-1000A equipment. I'm not looking for someone to engineer it for me, but general thoughts on pros/cons/feasability of solutions are appreciated. Thanks!