ECN Forum Forums General Topics of the Trade General Discussion Area Ampacity

White pipe? I've always seen orange. It's the wire that's white. It looks like zip cord, but I think it's #12. Enclosing it in conduit is optional. I've seen the stuff on roofs, where exposure to UV makes it blister and bubble.

What are the grounding requirements for a service done in zipcord?

Steve,
Are any of these Mil_Spec codes online or available to the average citizen? I'd be interested in how much they go above the NEC, weird practices, etc.

Mike

Yes, almost all the MIL-HDBKs and Tech Manuals dealing with facilities are unclassified and approved for public release. None of these are anything like NEC, though. In fact, I've never actually seen the specs that were used before IBC and NEC were invoked by UFC 1-200-01! But I've only been working power for about a year now; I worked electronics before this and never had to worry about it. (Edit: Nobody else here remembers it either- we've been using UFC for quite a while!)

Here's a site with a large # of MIL-HDBKs related to facilities: http://65.204.17.188//report/doc_ufc.html

I reference MIL-HDBK-1004/2-4, MIL-HDBK-419A and MIL-HDBK-411B a lot; I think they're all part of the UFC now, I just know them by their old numbers. There's a lot of good stuff in MIL-HDBK-1012/1 "ELECTRONIC FACILITIES ENGINEERING" too: http://www.wbdg.org/ccb/NAVFAC/DMMHNAV/1012_1.pdf

I use MIL-HDBK-1003/3 for HVAC, too, even off-base as it's free and I don't own a copy of Manual-J or Manual-S, lol...

It's almost all good practice and makes a lot of sense- NEC is not a design guide, it's a set of minimum standards- these are design guides, compiled in a form to keep consistant design good practice throughout the government. But the key is that every military command is its own AHJ, and all this guidance is merely that- guidance. There are very few hard and fast requirements we HAVE to follow, just a lot of recommendations we SHOULD follow, so in practice, we're free to approve/disapprove whatever we want, regardless of what UFC or NEC says. It's good to be your own AHJ, let me tell ya!

[This message has been edited by SteveFehr (edited 01-30-2007).]

ROFLOL!!!

My favorite Mexican wiring method is they will grease a piece of garden house, and put in a concrete pour. After the concrete cures a bit they pull it out (so they can re-sue it), and there you have it, a custom concrete wireway.

Back on topic:
Take a look at NEC 2005 310.60 (C) Engineering Supervision.
Under engineering supervision, conductor ampacity shall be permitted to be calculated by means of the following general formula.

[formula]

Basically if you have the engineering wire specs, excel, and can get the PE for the project to sign off on it, then you can pretty much throw T31016 out the window.

Using that formula for some wire manufactures 54A with #10 AWG THHN does not sound to far off.

Granted it won’t happen in general construction here in the US for #10, but there have been times when I have used it for special circumstances in installations that access or space made it a viable solution. Like an under slab feeder for a remodel that was too small for the new service in an existing 6 story building.

Grounding? What's that Senor?