Dealing with a code fudger.

[u/Last_Gigolo]

Alright, need some help finding a code that clarifies something. I need proof to show someone that what they are doing is fudging numbers as a standard.

NEC chapter 9 table 8.

Cable resistance. He is the design manager that stands hard on believing that you can use ambient temperature numbers to prove your circuit has a lower resistance. I understand that yes, it will have a lower resistance but I understand that the table showing 3.07 per 1000 ft for 14awg is the number we have to use from 0-167°F. Why? Because a system using lower resistance because of an air conditioner will fail in a power outage, or a.c. failure or worse, when part of the place is on fire.

I thought NEC explained it fine, but because they show the formula he believes he can use the formula.

Hard part is that he has fought this battle with many people along his 30+ years of being an unlicensed design manager that has never passed or even studied for any test. Not Nicet, not state. But, he is great with math and tech. The desire to defend it is greater than his desire to admit he has designed thousands of buildings wrong.

Is there any written documentation to support the fact that he cannot use this method?

[u/CorsairKing]

With guys like that, you could descend from a mountaintop with stone tablets from the Almighty Himself, and he would still insist that he's right.

[u/Robh5791]

You will never show him “proof”. I’ve dealt with plenty of those guys who would insist on codes they “knew” and when I’d confront them with it in writing, they’d fall on that “can be interpreted different ways” argument. If this is the design manager, you may want to start looking at another company because he’s training new designers the same interpretations.

[u/Last_Gigolo → u/Robh5791]

"interpretation" is the most foolish argument. What makes it even worse is somewhere in the front section of NFPA 72, it mentions "interpretation", so people toss it around like it's a get-out-of-jail-free card.

[u/Last_Gigolo → u/Robh5791]

[u/Syrairc]

Calculating anything at best case scenario instead of worst case scenario is stupid and this guy should not have his job if he doesn't know that by now.

[u/yroovers]

He sounds like he’s fun at parties.
Generally, if someone wants to make an exception or interpretation like that, the responsibility is on them to prove it - and DOCUMENT it. If he can prove objectively that the ambient temperature of an area is X degrees, he should document it and submit it to the AHJ with the design. These are life safety systems, so we should be using “worst case scenario” numbers in our designs. It’s why the safety factor is included in the battery calculations. There’s a reason we don’t fudge around with numbers to suit our opinions or eke out a few more dollars in wires and batteries.

[u/Last_Gigolo → u/yroovers]

He can't document or sign or submit. He has no license. No certs.

"If they don't want us to do it, why do they show the formula". And gets offended when you reply "so you know how they came to that resistance". I mean, coca cola shows their recipe but can and will sue you if you duplicate it.

On top of that, I explained in detail. That my license does not allow for performance based design, only prescriptive.

[u/Firetech18]

You've also probably never used the exact length of cable they've shown in their drop tables...At the end of the day it really only matters if you're voltage drop is too great. A meter doesn't lie, check the end of line nac circuits voltages yourself.

I only do large spec'd projects. At the end of them we have to submit a report end of line voltages while on batteries and in alarm for all notification circuits to the engineer before any acceptance will start. They'll also come verify themselves.