Jim Katen

Which roofing products have these warranties? - Jim Katen, Oregon

Sure, so long as, by doing so, you aren't putting too much load on the circuit. - Jim Katen, Oregon

That's a really great article on the subject. It's worth the cost of that back issue just to read the article. However, the article is very careful to avoid any discussion at all of the use of handle ties on multi-wire circuits. I suspect that the editors had some differnces of opinions on the subject and elected to avoid the issue entirely. Did you catch that? The entire idea of putting these on common-trip breakers is Dan's opinion. He even says he can't find any authoritative source for this opinion. I like Dan. I respect Dan. But sometimes he comes up with real doozys. That's some decent logic, but that's all. There are dozens, maybe even hundreds of things that we could recommend that would make an electrical system safer that go above and beyond the NEC requirements. Why choose this particular one as a poster child? Nope. That cite does not support his position. It's only dealing with a situation where you've got more than one device on the same yoke. Nope. Wrong again. It is not a "requirement." All true. But it's not a requirement. He's trying to make it sound as if it is. Oops. Looks like he couldn't find any. So the only authority he consulted told him he was wrong. - Jim Katen, Oregon

Every electrician out there knows about multi-wire circuits and how to safely work with them. In a lot of commercial wiring they're the rule, not the exception. The only time they becomes dangerous is when an amateur is messing with the wiring. I happen to be one of those people who think we should not be designing our electrical systems to coddle to amateurs. As far as I'm concerned, there is no "issue" to tackle. The NEC is abundantly clear on the subject. My advice is to let them be. - Jim Katen, Oregon

Double wall = B vent. I have the installation instructions for Ameri-vent, Metalfab & DuraVent, the only three manufacturers of B-vent material that I'm aware of. They all require 1" clearnace to combustible materials and they all say so on the product. They give off little heat when everything's working right. They get remarkably hot when things go wrong though. Well, that would get my curiousity up. I say you go out there and document the brand and model of this vent material. Take lots of pictures. I'd be particularly interested to see this sticker. If it turns out you're right & someone's trying to pull a scam, you can bill them. I wouldn't worry about the metal tape. It's not a problem. If you don't want to go out there, ask for a picture of the sticker and the name brand of the product. - Jim in Oregon

Rick, I'm unable to understand exactly what goes where in your description. Try it again but dumb it down for me. Explain it as you would to a child. In the meantime, I agree with what Brian said. Particular points to remember: * Each separate structure will need a grounding connection to earth (driven rod, Ufer, water pipe, etc.), unless there's only one circuit run to the structure. * You'll need to isolate the grounding and neutral conductors at separate buildings unless if there's a continuous metal path between them or unless if there's a 4-wire feed already in place. To answer Brian's question about how a panel on a pole fits into the NEC -- I don't know. However, I've heard people argue that a pole or pedestal qualifies as a "structure" (NEC definition of structure: That which is built or constructed.) Re-read the section with that in mind and all should be revealed. I hope this helps. - Jim Katen, Oregon Edit for grammar

Good gravy! Did they tap it ahead of the service disconnect? Or did they tap it off the load side of that left disconnect? You know, I don't recommend that anyone open a hot gutter, but honestly I don't think I could have resisted in this case. I'll bet there's a disaster in there. I'm also curious about the holes in the stucco and the unused blue plastic screw sheaths. Something's rotten in Denmark. - Jim Katen, Oregon

Monte, Flexible metallic conduit and armored cable are two different things. You're correct about 3/8 inch FMC being limited to 6 feet. In fact, there are a bunch of other limitations on conduit this small. Check out article 348. I believe what you saw in this building was armored cable. You can run this stuff as far as you want (within the limitations of voltage drop, of course). Read all about it in article 320. It's perfectly ok to use the cable sheathing for equipment grounding. - Jim Katen, Oregon

The guys over at Mike Holt's forum more or less agreed with my line of reasoning. Here was one particularly well put response: - Jim Katen, Oregon

There are two basic types of arcing in a household electrical system, series and parallel. Series arcs occur when there’s a break in a wire or when there’s a loose connection; the electricity is traveling along its intended path but has to jump over the break. Parallel arcs happen when there’s a short circuit between two different conductors, for instance between a hot and a neutral or between a hot and a ground. This last condition, a short between a hot and a ground is also called a ground fault. The present generation of branch circuit AFCIs only protects against parallel arcs, they’re useless against series arcs such as those you’d get with old aluminum wiring, loose connections at receptacle terminals or stab-backs, loose wire nut connections and broken or partially broken wires. They will protect against hot-to-hot shorts and hot-to-ground shorts. Of course regular breakers will protect against those too. The AFCI’s will just do it more quickly and at a lower threshold. So for all those times when you drive a nail through a piece of Romex and it makes enough of a path between the hot and the ground to cause an arc, but not enough of a path to trip a conventional breaker, the AFCI will save your butt. In the final analysis, these things only protect against a tiny portion of the arcs that can happen out there (beyond what regular circuit breakers do). That said, the next generation of AFCIs should be much more useful. - Jim Katen, Oregon

Hey, don't laugh, the man knows his bonding. Until I can see what's going on in that gutter, I'm going to guess that the pool panel is also a service panel. I think you're right. Though "cut" might not be the right word. Maybe "disconnected," or "separated." Not if it's a service disconnect. And you can't tell that without either opening the gutter or switching things off to see what goes dead. (I don't recommend either one.) In any case, the 100 amp backfed main in that panel should be fastened in place with an accessory clip. - Jim Katen, Oregon

The documentation is cast into the moulded case of every breaker. Other than that, try here: - Jim Katen

No, the heat is normal. At least that's what we think now. Wait ten years and ask again. The AFCI breakers have an internal power supply that generates some heat even when there's no load on the circuit. In addition, when there is a load on the circuit, there'll be some I²R losses that create heat just as there would be in a normal breaker. If the panel has more than a few AFCIs and they're stacked together, the problem gets more severe. As I recall, typical residential breakers are rated for use at an ambient temperature of about 104 degrees. They'll still work at higher temperatures, but they may trip more easily. If someone's having a problem with nuisance tripping and there's a big stack of AFCIs, it might be worth separating them to see if it helps. By the way, I'm becoming more and more convinced that AFCIs are pretty much useless. At least they certainly aren't worth the aggregate amount of money that is being spent on them across the nation. - Jim Katen

I wrote most of it. (Stole some from Greg Devault in Seattle.) - Jim Katen, Oregon

It's a butt quilt. Wow, that brings back memories. Someday, if you can get me drunk, I'll tell you about the year I spent working with my dad at the "Rough & Ready Underwear Company." - Jim Katen

The prohibition against this supposedly comes from 312.8. The trick phrase here is, “for that purpose.â€

I can't imagine what could've caused that series of events, unless. . . I don't suppose you had a "brownie" with your lunch that day? - Jim Katen, Oregon

It's a nasty old panel. Replace it. Of course you need to replace the compressor wiring as well. If you want to know more about Zinsco panels, search past posts on this forum. There ought to be plenty to read. - Jim Katen, Oregon

I don't know enough about NAHI to make any intelligent comment on their particular seminars. However, based on my experiences of other associations' seminars, I think you get way more out of these things by attending the whole event than by picking a class here & there. I learn more in the halls than I do in the classes. - Jim Katen, Oregon

Hell, I don't know. I just repeat the stuff that Douglas explained to me 10 years ago. I never figured anyone was actually paying attention let alone applying critical thinking. FWIW, here's my guess. I figure it's like seat belts. My car has both front and side-impact air bags. If I'm in an accident, the air bags are designed to protect me. But I'm also wearing a seat belt. It's a redundant safety feature. My hunch is that it's something along those lines. We want the breaker to be as small as possible and still not be a nuisance when the motor starts. I'll post the question over at Mike Holt's forum and see what else folks say. - Jim Katen, Oregon

The requirements for all the stuff on the AC unit's nameplate are in 440.4(A). 110.3(b) requires the electrician to install the system per the nameplate. Is that what you were wondering? No. In an air conditioning circuit, the overload protection comes from the compressor motor's thermal protection device. It's built in and it protects both the motor and the conductors. The breaker or fuse is there to protect against ground faults and line-to-line shorts. If we sized the breaker to protect the wire at it's rated ampacity, we'd get constant nuisance trips on startup when the motor draws lots of current. Make sense? - Jim Katen, Oregon

No, it doesn't. It just says each grounded (not grounding) conductor must end in its own terminal. The panel instructions I've read say that you can place two and sometimes three grounding conductors under a designated terminal. These would be the equipment grounding conductors of which you speak. - Jim Katen, Oregon

Monte, I'd never articulated my inspection method before. Always did wonder where the time went. . . 15 Exterior & grounds 15 Roof 15 Attic (Go outside to dust off if necessary.) 05 Check exterior doors from the interior. 30 Stop & write. 00 Start heating or AC 15 Kitchen (start dishwasher) 30 Bathrooms 20 General interiors 10 Stop & write 05 Garage 30 HVAC & water heater 10 Electrical 10 Stop & write 20 Crawlspace 20 Finish writing 45 Review report with client 295 Damn. One of these days, I'm going to have to tighten up my routine. - Jim Katen, Oregon

We hear this one every so often. Let me be the first to say, I have no idea what's causing it. How do you know they have voltage? Are you using a multimeter or one of those volt-stick things? - Jim Katen