Is this Dangerous?

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jap

Senior Member
Occupation
Electrician
It is a very neat looking wiring and tape job.

Makes me think the poor guy takes so much pride in his work he probably is none the wiser about the wire size not being large enough or the danger that was created by terminating the line on the load side terminals.

I'd definitely bring the issue up with the owner and whoever it was that did the tenant wiring to get it straightened out.

JAP>
 

Jamesco

Senior Member
Location
Iowa
Occupation
Master Electrician
"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

Maybe a dumb question.
What if the lugs were rated 90c? Lugs at the transformer could easily be changed to 90c. What are the chances the lugs on the line side of disconnect switch are rated for 90c? If not, can the lugs be field changed to 90c without voiding the UL listing or violating 110 or some other article in the code?

Just trying to save the contractor some money on fixing his/his electrician's screw up. He would only then have to splice the wires at the switch and reconnect them the correct way.
Maybe 3 to 4 man hours tops.
 
Maybe a dumb question.
What if the lugs were rated 90c? Lugs at the transformer could easily be changed to 90c. What are the chances the lugs on the line side of disconnect switch are rated for 90c? If not, can the lugs be field changed to 90c without voiding the UL listing or violating 110 or some other article in the code?

Just trying to save the contractor some money on fixing his/his electrician's screw up. He would only then have to splice the wires at the switch and reconnect them the correct way.
Maybe 3 to 4 man hours tops.

It is not just the lug, but the equipment that needs to be rated 90 degree. Although almost every light is rated 90, I don't believe there is any equipment terminals rated 90. If they were spliced, he could indeed transition to the larger conductor for the last bit. Some say the transition needs to be in a separate enclosure citing UL testing procedures I believe.
 

infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician
I agree Electro, 90° C lugs aren't going to change anything due to the switch being rated for 75° C. 350 amps fuses would probably work but that would depend on the load and if the customer is actually paying for 400 amps would they let it slide.
 

jim dungar

Moderator
Staff member
Location
Wisconsin
Occupation
PE (Retired) - Power Systems
It is not just the lug, but the equipment that needs to be rated 90 degree.

Actually it is the termination that needs to be rated 90C.;)
UL doesn't list any overcurrent protective device with terminations above 75C. Even the 100% rated devices require 90C conductors that are sized using the 75C tables.
 

Jamesco

Senior Member
Location
Iowa
Occupation
Master Electrician
/
It is not just the lug, but the equipment that needs to be rated 90 degree. Although almost every light is rated 90, I don't believe there is any equipment terminals rated 90. If they were spliced, he could indeed transition to the larger conductor for the last bit. Some say the transition needs to be in a separate enclosure citing UL testing procedures I believe.

Thanks electrofelon for your response.

A simple Google search:
When terminations are on circuit breakers or inside equipment such as panelboards, motor control centers, switchboards, eclosures, safety switches, etc., follow the temperature rating identified on the equipment labeling instead of the component rating of the lug itself. Manufacturers commonly use 90 °C-rated lugs (i.e., marked AL9CU) on equipment rated only 60 °C or 75 °C. The use of the 90 °C-rated lug in this type of equipment does not allow the installer to use 90 °C wire at the 90 °C ampacity.


The Underwriters Laboratories® General Information on Electrical Equipment Directory states the following about terminations:
“A 75 °C or 90 °C temperature marking on a terminal (e.g., AL7, CU7AL, AL7CU or AL9, CU9AL, AL9CU) does not in itself indicate that a 75 °C or 90 °C insulated wire can be used unless the equipment in which the terminals are installed is marked for 75 °C or 90 °C.” Review the labeling of all devices and equipment for installation guidelines and restrictions.
https://www.se.com/us/en/faqs/FA176152/

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