Douglas Hansen

Have any of them offered a reason for that one? Ground rods are copper-clad to prevent corrosion from contact with soil. Concrete, on the other hand, can be slightly corrosive to copper. Perhaps there is some concern about the soils down there creating a more aggressive chemical action. The original Ufer grounds were copper wires laid into foundation footings, and even today the NEC allows a concrete-encased electrode to consist of 20 feet of 4 AWG copper in the footings. They aren't going to show you a C&V on this from a national code.

In the old days, these problems would inspire unique solutions for each system. Today, the inverters that convert photovoltaic DC to AC are listed as "utility interactive." They need to see the signal from the utility and synchronize to its frequency. When it isn't there they shut down. There is no danger to the utility from a utility-interactive inverter. For the same reason, a backfed circuit breaker from a utility-interactive inverter does not require a locking mechanism to hold it in place. If you pulled it out of the panel, the breaker jaws would no longer be live; the inverter will shut down. With other backfed breakers, you would have a tiger by the tail. Very large arrays can cause issues with a utility because of increased short-circuit current. Small ones don't have that problem.

Section 90.2(B)&© of the NEC does indeed mean that electric utilities are exempt from the NEC. I'm sorry if you assume the implication of that statement is that they make up their own unsafe rules. It would be great if every utility behaved like yours or the ones described in Tom Raymond's post, but they don't. Here in California, our utilities are "regulated" by PUC orders 95 and 128, each hundreds of pages long, and each modeled on the NESC. They are widely ignored. Our local utility (sponsor of the San Bruno gas explosion) will not respond to a call for much less than their equipment being on fire. I have been through too many just plain ridiculous situations with them, including refusing to respond to broken service drop conductors. For a simple service update, they require a $2,000 deposit for "engineering services" which are nonexistent, and the process to recover the deposit (or what they are willing to part with) takes months. As far as the utility sizing conductors based on their anticipation of the customer's load, rather than the rating of the service equipment or disconnects, the worst I saw was an 800-amp 3-phase switchboard fed by 250kcmil aluminum. Equipment all through the facility was failing due to the voltage drop caused by the utility's undersized conductors. That was an example of them just making something up, and the customer taking it on the chin. Last year I inspected one where tens of thousands of dollars worth of equipment had been destroyed by water vapor because the utility forgot to seal their underground conduits. The facility was about 5 feet above the high tide line. The utility refuses to allow the contractor to seal them, insisting that only their own folks get to do that work. They take no responsibility when they subsequently forget to do it. I could go on but I think you get the idea. I know there are many utilities that do care about getting it right. I wish ours was one of them.

My favorite of late has been the phone call from "Microsoft" telling me that I have a virus. I usually just hang up, but one day they got me while I was driving so I decided to play along. They asked me if I was sitting in front of the computer, and I assured them I was. They proceeded to instruct me on how to go into MSCONFIG and a few other places to basically hand them control of the computer. After playing very dumb (not hard for me) and making them repeat every instruction a half dozen or so times, I did all I could to make them think they had really hooked a live one, then just hung up.

The size of the service drop conductors is not a problem. Here in the U.S., the utility is exempt from the NEC (per NEC 90.2C) and they are free to size their conductors based on anticipated load, not the rating of connected equipment. I don't know if it is the same up there. John will chime in with that answer. Conductors in free air also are allowed much higher ampacity than those in a raceway. Aluminum 2 AWG conductors are given an ampacity of 135 amps in table 310.17, though I think a case could be made for going straight to the 90 degree ampacity of 150 amps. My only Canadian Electrical Code is very old, yet seems to have similar numbers (only 140 amps though for 90 degree insulation).

There is no minimum bending radius for individual conductors, only for cable assemblies. There is a rule for the amount of space needed between the panel wall and the terminals. If the conductors exit the wall opposite the terminals, it is based on table 312.6(B) and assumes two bends will be needed in that space. If you look at the numbers in the table, it will work out to somewhere between 5 and 7 times the diameter of the cable most likely to be used in the lugs. You often see very sharp factory-made bends on service equipment. It isn't a problem. At low (<600) voltages, it isn't going to affect conductivity, strands of conductors aren't going to be stretched or damaged, and insulation will remain intact. Medium voltage cables with layers of dielectric insulation do have a minimum bending radius. House wiring doesn't. What matters is that the conductors lay into the lugs without adding stress to the connection. That is much easier to do if you make a loop rather than trying to run them the shortest distance. A proposal was made to add a minimum bending radius in the runup to the 1978 code. It received no support.

If you are talking about a bend in the individual conductors inside the panel, with no sheathing on them, that is how I would wire it. I prefer making that loop so there is something there in case the connections at the terminals ever need to be redone. 338.24 only applies to the cable with the sheathing in place. If what you are talking about still had the sheathing on it inside the panel, I would agree the electrician was a bit loopy.

Jim has always been really good at everything he has tried. The home inspection profession was lucky to have him, though I think he has found something closer to his true calling. Here is a link to some of the work he has produced in his new gig. http://www.bu.edu/statehouse/tag/jim-morrison/

Thanks Eric Clicking on your link it turns out even my local HD store has 28 of them in stock.

They are a specialty item, and probably cost more the $2 these days. I doubt they sell them in home improvement centers. I've only seen them in electrical supply houses. You can see the letters on the yoke and they are also embossed on the back. Click to Enlarge 28.63 KB Click to Enlarge 41.11 KB

Electrical components are tested and listed by "Nationally Recognized Testing Laboratories" (NRTLs). The most prominent NRTL is UL. NRTLs do not arbitrarily choose the manner in which components are tested. They are tested to published standards. For receptacles, the standard is ANSI/UL 498, and for snap switches it is ANSI/UL 20. CPSC is not a nationally recognized testing laboratory. The engineer who provided the bulk of "their" research on aluminum is not an electrical engineer. The test protocols which were followed for whatever research led to this CPSC statement have not been published, and there is no reason to imagine they were conducted in accordance with the procedures of the published standards. Per the NEC and the standards above, snap switches, and receptacles rated 20 amps or less, must be rated CO/ALR when directly connected by aluminum conductors. Other types of receptacles may be connected by pigtailing copper and using a suitable connector between the different materials. If you examine a CO/ALR receptacle or switch, you will see that the underside of the terminal screw head has a saw-tooth pattern designed to bite into the conductor and increase the area of surface contact between the materials. Of course they must also be applied at their proper torque setting (20 inch pounds).

We've updated the downloadable article on FPE at our web site. http://www.codecheck.com/cc/articles.html

A conductor should never loop around a screw in such a manner that the wire crosses over itself. If what you are talking about is placing a bend in the wire in such a manner that it resembles the letter omega then it is possible to go through the screw in the box or on the receptacle, though it isn't making things any easier for anyone. What's wrong with running a wire from the box and pigtailing the other equipment grounds to it?

The down conductors of lightning protection systems should be kept at least 6 feet away from metal parts of electrical equipment (like service masts) to prevent sideflash. The electrode for the lightning protection system is required to be bonded the grounding electrode system of the house power (NEC 250.106). What you saw is very similar to the bonding requirement we now have for CSST, and probably using the same logic. If the earth voltage is elevated, you want ALL the metal systems in the structure to rise to the same voltage - you don't want there to be a large potential between them within the structure. There's nothing wrong with the bond to the house side of the gas line. It sounds like the bond to the house power system might be what's missing.

The IRC quotation is only half the story. If you look at the source of that text that was extracted from 210.8 in the NEC, you see a fine-print note directing you to also look at sections 760.41(B) and 760.121(B) in the article on fire alarm systems. Those sections tell us that the branch circuit for the fire alarm has to be an individual circuit with no other loads, that the circuit disconnecting means shall have red identification, that it shall be accessible only to qualified personnel, and that it shall not be supplied through a GFCI. The IRC does not have a section on fire alarms, so they did not bring in this language. The idea is that they do not want someone testing it since these are central station alarms. The fire alarm company and fire marshal can have a key to the fire alarm control; the homeowner can't. The last thing the fire department needs is to get a false alarm because someone pressed a GFCI test button that said "test monthly." Keep up the good work.

I agree with Jim, of course, while at the same time admiring John's commitment to getting it right for his clients and the homeowner. The question of where to draw the line takes judgment and isn't always the same in every situation.

We have lots of stucco here, and have been using it for close to 100 years. Of the thousands of buildings I've looked at with hardcoat stucco, I can't recall one that was quite as FUBAR as yours. The texture they were attempting is called a trowel sweep. It is supposed to be applied in two layers over the base coat, and be troweled in such a way as to leave a narrow ridge or bead at the edges of the fan shapes; whoever did this applied it way too thick and I can't imagine that any of the curing times or conditions were correct. The only good news is that the staining below the horizontal crack indicates water emerging from it, which implies there is some sort of WRB behind this mess. I wouldn't go so far as to bet on flashings. Perhaps when they tear it off the walls they won't be completely damaged.

Hello Joseph I would think you have plenty of room in your panel to install a breaker that feeds your air conditioners. The available room, in terms of amperage, is based on the total connected load, not the ratings of the breakers. The breakers are never assumed to be simultaneously operating near their maximum capacity. Tapping into the main feeder lugs would be a very bad thing. The feeders to the AC panel would be an unprotected extension of the service entrance conductors, without any form of overcurrent protection, and the lugs themselves would not be rated for two conductors. A couple of 3-ton air conditioning units is not all that large a load. The instructions might be calling for a certain maximum size overcurrent protection device to handle the inrush current that occurs when they start up, and that only lasts for about 1/10 of a second. During normal operation, I doubt the two of them combined are going to draw more than 40 amps. There are lots of other ways to do it. You could run individual branch circuits from this service panel to the AC units, or you could install a $ubpanel. Either way, you are going to end up needing disconnects within sight of the AC units. If you are dealing with an AC sub, I suggest you ask them for their preference. As to other choices of how to do it, please realize you are getting close here to asking an internet forum for design advice. None of us are really going to be comfortable providing that, though I do applaud the diligence you are applying to the planning stages of the project.

I agree with the "specified amount" portion John. I don't think that means things will stay there. IR testing in industrial facilities often identifies terminals that have weakened over time. The idea of just tightening things again isn't necessarily the right thing to do. If you retighten something, you might actually cut through part of the conductor. Sometimes the right way is to remove the conductor, cut and strip it, and reinstall it. That would be especially important with aluminum. Over-tightening can be just as bad as not enough torque. Around here, we have at least one jurisdiction that requires the contractor to have a torque wrench and torque screwdriver, and to torque the connections in the inspector's presence. If they call for inspection without those tools, it is an automatic turndown and reinspection fee.

For 3-wire circuits, yes. A multiwire circuit always had to have a red conductor, and the red conductors all had to originate from the same bus. The circuits that were not three wire could use black from either bus if they were part of a cable system. If they were pulled through raceways, then even the non-MWB circuits had to match the color for their bus. This even applied to knob and tube. For 120/208 three phase the convention of black, red, blue was mandated in the code. So was voltage drop. All of that was dropped in 1975.

Basically for the same reason Bob posted - problems for someone else down the road. The conductors are not going to care one bit about the of color their insulation. It is entirely a human factors issue. One reason things follow certain conventions as far as wiring practice is so that the next guy in will understand what is happening. If the next guy is going to add 3-wire circuits he will want to be able to visually identify the pole where each circuit originates, and having them inconsistent creates confusion. The code used to require that once you picked a certain bus to be red, you had to stay with it throughout the building. The 1968 NEC was the last to say that: "All circuit conductors of the same color shall be connected to the same ungrounded feeder conductor throughout the installation." (210-5). That turned into a non-enforceable fine print note in 1971 and was deleted in 1975. That was the year the lawyers took over, and did all they could to pretend that the NEC is not a design specification. In actual practice, as promoted by IBEW and NECA, this is still the "right" way to do it. I don't know a person working with the tools for a living that would walk away from it with one red wire on one bus and the others on another bus. So the difference it will make comes down to perception. A journeyman working on this thing in the future will know that this panel was not done by his brethren. That said, I am sure you will all agree that Mr. Velder's work is exemplary for someone not in the electrical trades, and that he has done a far better job wiring this thing than most of the stuff you look at every day. On top of that, he cared enough about getting it right to post it on here. I think he is entitled to know everything we can tell him about what is right and what isn't.

While agreeing with Bob 100% here, it is too late to change most of those things as the wires have already been trimmed to length. One other T9C thing - the red-black pattern isn't consistent. The two red wires at the top connect to the left bus, and the one at the lower left connects to the right bus.

On this particular panel, the screw for the main bonding jumper that John is talking about would go in that small notch at the lower left, just under the left neutral terminal bar. The screw should have been included with the panel, and will have a slightly green color. Assuming you can't find the screw, the bonding jumper will need to be sized based upon the size of the service entrance cables, probably 4 AWG. I can't be sure from the picture, but it looks like you might have 6 AWG in there now. Where is the grounding electrode conductor going to connect to this?

Thanks everyone. So far I think the closest answer was John's theory of an extraterrestrial Stonehenge. I checked as best I could from google, and it is not a Nexrad. Each dome is about 30 inches across, and secured with bolts with wing nuts. It looks like a 2-person job to try to take one of them off (not that I would try). I keep hoping I will run into a ranger up there (this fenced off area is a half mile past the end of the public road, which ends at a locked gate). Maybe if I do run into a ranger they can explain it. The Marconi stuff is about 5 miles West of Mt. Vision. This photo is taken from Mt. Vision, looking at Point Reyes. Drake's Bay is on the left and the foreground is Drake's Estero. The radio antennae are to the right of the area in this photo. I didn't realize all the history of this, and it is right near us. Thanks! Click to Enlarge 45.52 KB

This strange circular array of metal domes is behind a locked fence at the top of Mt. Vision, on the Point Reyes Peninsula (northern California). It's the top of the hill behind my house. Any guesses what it does? Whatever it is does not seem to involve electricity, at least not now. Some of the domes have been replaced. Thanks Click to Enlarge 56.64 KB