RACERX67HD
Member
- Location
- GIRARD OHIO
- Occupation
- Chief Electrical Design Engineer
Hello All,
I'm a new user here, but I have been here many times when I've been perplexed and gained some great insight. So, now I'm hoping I can get some answers on something perplexing me with a customer. It's easier if I show illustrations as well, but I tried and no upload or even ability to paste a snip-it in this post.
So, here goes, I'm the Chief Electrical Engineer with a Systems Integrator, and our shop is a UL508A panel shop, and we have a customer we build a few different styles of panels for all have to be certified UL508A. I will try to explain the best I can below. Now, this is where I'm getting perplexed.
The Panel has a Fused Main Disconnect with LPJ-30SP Fuses which are rated for 300kA up to 600VAC. That wires to a Line reactor, then to (3) MPCBs. The First MPCB of which, is a 140M-C2T High Magnetic Trip, rated for 100kA in single-use Motors Starter Combo, but only 10kA, in Grouped Motor Starters. The customer wants to change this to a 140M-C2E Standard Magnetic Trip which is 65kA in a grouped scenario, to boost the SCCR of their cabinet (not sure why it's not like this is a new design, they've been building and certifying them this way for a while), but leave the rest at the 140M-C2T. I told them, you can make this one 200kA if the rest are 10kA or lower, you have to use the lowest value in the panel for SCCR.
But that's not even the real point. I've been in this industry for 30+ years and have never run into this before. Designing Transfer Switch and Switchgear for close to 10 of those years and typically we were 65, or 100kA, but occasionally it was 35, or 42kA. Plus, I'm not sure if the MPCB's kA is de-rated on Multiple Drives vs Motor Starter Combo going direct to the Motors and no manual tells me that. I'm planning on changing them all to the 140M-C2E, but it's really been bugging me. This is a first for me in my 30+ years,
I'm a new user here, but I have been here many times when I've been perplexed and gained some great insight. So, now I'm hoping I can get some answers on something perplexing me with a customer. It's easier if I show illustrations as well, but I tried and no upload or even ability to paste a snip-it in this post.
So, here goes, I'm the Chief Electrical Engineer with a Systems Integrator, and our shop is a UL508A panel shop, and we have a customer we build a few different styles of panels for all have to be certified UL508A. I will try to explain the best I can below. Now, this is where I'm getting perplexed.
The Panel has a Fused Main Disconnect with LPJ-30SP Fuses which are rated for 300kA up to 600VAC. That wires to a Line reactor, then to (3) MPCBs. The First MPCB of which, is a 140M-C2T High Magnetic Trip, rated for 100kA in single-use Motors Starter Combo, but only 10kA, in Grouped Motor Starters. The customer wants to change this to a 140M-C2E Standard Magnetic Trip which is 65kA in a grouped scenario, to boost the SCCR of their cabinet (not sure why it's not like this is a new design, they've been building and certifying them this way for a while), but leave the rest at the 140M-C2T. I told them, you can make this one 200kA if the rest are 10kA or lower, you have to use the lowest value in the panel for SCCR.
But that's not even the real point. I've been in this industry for 30+ years and have never run into this before. Designing Transfer Switch and Switchgear for close to 10 of those years and typically we were 65, or 100kA, but occasionally it was 35, or 42kA. Plus, I'm not sure if the MPCB's kA is de-rated on Multiple Drives vs Motor Starter Combo going direct to the Motors and no manual tells me that. I'm planning on changing them all to the 140M-C2E, but it's really been bugging me. This is a first for me in my 30+ years,
