- Occupation
- Licensed Electrician
2020 code has a requirement for a disconnect for a fused disconnect.
Is this Dangerous?
- Thread starter infinity
- Start date
- Status
electrofelon
Senior Member
- Location
- Cherry Valley NY, Seattle, WA
I admit it took me a minute to see what was wrong, I was looking way to hard. I must have been subconsciously mesmerized by the tape job 
- Location
- New Jersey
- Occupation
- Journeyman Electrician
They did use a lot of tape.I admit it took me a minute to see what was wrong, I was looking way to hard. I must have been subconsciously mesmerized by the tape job
- Location
- Connecticut
- Occupation
- Engineer
The fuses aren't "at the secondary." They're downstream from the secondary.
oldsparky52
Senior Member
- Location
- Wilmington, NC USA
So, curious, would you replace the conductors or splice them in that disconnect to extend them to the correct lugs? I think I would splice them (does that make me a hack?).
- Location
- Tennessee NEC:2017
- Occupation
- Semi-Retired Electrician
Are you guys saying the disconnect on the left should have the conductors reversed, meaning top goes where bottom ones are and vice-versa? Or the cabinet flipped around?
gadfly56
Senior Member
- Location
- New Jersey
- Occupation
- Professional Engineer, Fire & Life Safety
Yes, that's the idea, although I don't think you could simply flip the cabinet. Isn't there a requirement that "ON" be "up"?
kwired
Electron manager
- Location
- NE Nebraska
- Occupation
- EC
"next size up" rule only would apply to the load side of the fuses here
the non protected secondary conductors would need to have ampacity not less than 400 here
winnie
Senior Member
- Location
- Springfield, MA, USA
- Occupation
- Electric motor research
It seems silly to me that the next size up rule does not apply here. The difference in ampacity vs short circuit protection by the primary fuses would seem to make little difference, and the secondary fuses provide just fine overload protection.
I am far more concerned about the line vs load side disconnect issue.
-Jon
I am far more concerned about the line vs load side disconnect issue.
-Jon
- Location
- Wisconsin
- Occupation
- PE (Retired) - Power Systems
I would probably look at replacing the fusible switch with a breaker, and provide properly sized conductors from the transformer secondary.
oldsparky52
Senior Member
- Location
- Wilmington, NC USA
Yea, I did forget the conductors were too small. Well, I still think the most cost effective way to do it would be to use that switch, splice the load conductors so they reach the proper lugs and install (like you said) properly sized conductors from the transformer secondary.
oldsparky52
Senior Member
- Location
- Wilmington, NC USA
If the load allows it, could they replace the 400-amp fuses with 350-amp fuses and the wire size be okay?
Me too!I admit it took me a minute to see what was wrong, I was looking way to hard. I must have been subconsciously mesmerized by the tape job
petersonra
Senior Member
- Location
- Northern illinois
- Occupation
- engineer
This is one of those convoluted code requirements that makes zero sense but the issue is the conductors from the transformer to the fuses.
ptonsparky
Tom
- Occupation
- EC - retired
winnie
Senior Member
- Location
- Springfield, MA, USA
- Occupation
- Electric motor research
Just turn the AC to less than 68F
ptonsparky
Tom
- Occupation
- EC - retired
More than...
- Location
- Connecticut
- Occupation
- Engineer
Less than 68F...to increase conductor ampacity.
winnie
Senior Member
- Location
- Springfield, MA, USA
- Occupation
- Electric motor research
Damn, I could have sworn that the 'ambient temperature correction factors' went below 21C. But the tables only get us to 399A for 500kcmil
-Jon
-Jon
- Location
- Connecticut
- Occupation
- Engineer
- Status