Douglas Hansen

What Jim said. Also - The markings in your first photo indicate that aluminum wire is acceptable. The "SWD" in the first photo means "switching device" meaning that the prototype of this breaker is also listed for use as a switch for fluorescent lighting.

A friend in North Carolina has a house in the woods in the smokies, and is finding what he thinks are subterranean termites in his garage (and in the firewood stacked outside it). I'm not familiar with bug issues in that part of the world. Are bait stations a good idea?

Water heaters around here ship with a TPRV pre-installed in the side of the water heater, within the top six inches of the tank. The valve is underwater, and it is much simpler to introduce air to the tank by opening a hot water tap. You're welcome to it; I'm honored to find anyone thinking my stuff is worth repeating. FWIW, the ultimate water heater nerds are Larry and Suzanne Weingarten, authors of The Water Heater Workboook. http://www.waterheaterrescue.com/pages/ ... asics.html It is a treasure of information.

With a gas-fired water heater, there is some value to draining the tank if you do this from the time the water heater is new. If it hasn't been done in a few years, it isn't likely to accomplish anything. It also isn't that hard to do - just open a tap inside at a fixture to prevent a vacuum, shut off the water valve at the top of the WH, and turn the gas to the pilot setting. A couple of things can be done to extend the life of a water heater beyond the manufacturer's warranty. One is to replace the dip tube with one that is curved on the end, so that the water on the bottom of the tank is agitated. Sediment will mix with the water going to the taps instead of accumulating on the bottom of the tank. Another is to install a second sacrificial anode (some water heaters have an extra fitting for this). The difference between a 5-year manufacturers warranty and a 10-year warranty is a second anode. Large commercial water heaters sometimes have a cleanout opening where the sediment can be scooped out after draining the tank. Water heaters in my part of the world (hard water) often fail right after the new homeowner moves in. If the utilities are off for any period of time, the sediment in the bottom of the tank is more likely to stick to the tank. The first time it is heated up again, water that reaches boiling in the sediment cavities will dislodge it, sometimes taking a piece of the tank with it, and causing a leak.

You don't see very many 25-amp breakers, whereas 25-amp fuses are readily available. In this case, the 25-amp fuse meets the manufacturer's requirement, and the 30-amp breaker is unquestionably OK for the 10AWG wire. I will bet that the nameplate of the unit would have allowed a smaller wire, and that it said something like "min. circuit ampacity 19 amps." So this begs the question, what if they had used a 12AWG wire? Would it still be OK with the 30-amp breaker? I say yes. In the NEC, 240.4(D)&G) kick this back to article 440, and the fuse satisfies everything that 440.4(B) requires for protection of the AC unit. Neither the breaker or the fuse is providing overload protection. They are there only to protect against short circuits and ground faults. The AC compressor has overload protection built in. If you could find a 25-amp breaker to replace the existing breaker, it would accomplish absolutely nothing in terms of the safe and proper operation of this equipment. Before we grant any kudos to the electrician for oversizing the wire to the AC, realize that he probably didn't know what size unit they were going to put out there, and that he is probably the same bozo who strung a wire through the air to the a-coil in the attic. Douglas Hansen www.codecheck.com

I'm trying to clear off some shelf space, and would like to sell the books listed in the attached file. If you are interested in any of them, please contact me at Douglas@Codecheck.com . I would need to add shipping costs to the prices listed. If you are in California, sales tax would also apply, even though selling these kinds of books is not part of my normal business. Thank you Douglas Hansen Download Attachment: Code Books for Sale.pdf 101.56 KB

Greg - When you run into one of these again, could you take a picture to share with us? It certainly seems like a product we should be using out here, though I have never seen it. I have a project right now with two conduits going from a meter pedestal down to two buildings that are about 25 feet lower in elevation. It seems that these slip joints would solve the problem of water rising in the conduits at the buildings. The other ways we deal with the water problem are to have a drain/pull box outside the downhill structure, or to put an upside down wye in the riser. Thanks Douglas Hansen

I thought that a slip joint for ground movement is something different than an expansion fitting. I think you are correct. An expansion joint is listed for a predictable amount of expansion/contraction between two fixed points. Frost heave or ground settlement are less predictable. What Carlon calls a "slip meter riser" is longer than an expansion joint. I've been confused by this, in part because the informational note for 300.5(J) mentions "expansion joints" and isn't really correlated to the UL standards for such products. http://www.carlon.com/Master%20Catalog/ ... ochure.pdf I like the idea of the product in the link above because it will also function as a drain. Douglas Hansen

Chad, if this is just supporting the floor frame, and the rest of the building frame is wood, it seems unlikely to be energized. Bonding is never going to hurt, but in this scenario I don't see it being required. I agree with Bill. The converse of this question comes up fairly often, i.e., when is the building steel a grounding electrode? The answer these days seems to be in the affirmative when it is bonded to the Ufer. BTW, why did they install the ground rods? If he really did have his "re-barb" as the grounding electrode, and he has a plastic water service, the rods weren't really required. Of course, a lot of local guys want to see them regardless, and I wouldn't quibble over it. As long as they are all bonded together, the more electrodes the merrier. Douglas

RM: Did they make a rag wrap solid aluminum cable? DH: Yes - see attached photo Click to Enlarge 10.71 KB

"Handle tie" is the term you find in the NEC [240.15(B)].

In addition to the expansion of the required locations, the AFCIs must also be "combination" type rather than "branch feeder" types. Cutler-Hammer has been dumping their older branch feeder types onto the market, and if that is what you have, you will not be allowed to use them if the inspector actually pays attention. Of course, we are talking about the same inspector who oversimplified the rule for where AFCIs are required, so he might miss this one. None the less, if they are branch feeder types they will provide nowhere near the added safety of a "combination" type, and you should consider dumping them for that reason alone. If you buy a Seimens panel, you could also have multiwire circuits on your AFCIs, which can be a good thing for lowering your voltage drop losses and for simplifying the number of home runs. Other brands do not make AFCIs that support multiwire circuits. Last, I would stay away from Square D (at least the Homeline stuff) because the breakers cover the neutral bar. There are other space issues with a lot of their Homeline stuff. I concur with everyone else's advice about getting a full 40-slot panel. Douglas Hansen

Our need for logical categories has us wanting to pick one of these sets of rules and apply a particular installation to those rules. However, it isn't a question that has to be answered when we follow the appliance manufacturer's instructions. As an example, some appliances allow the two pipes to be joined into a coaxial plastic pipe so that you only have one sidewall exit. Those termination kits are easy to visualize as "direct vent" but they don't have to be called that. That same appliance may also have an instruction allowing two pipes with a certain minimum or maximum distance between their terminations, or a single vent pipe with combustion air from indoors. The workmanship in the attached photos is terrible. Click to Enlarge 32.99 KB Click to Enlarge 32.64 KB DH

I think Mike is describing it correctly. The rule being quoted from NFPA 54 is repreated in all of the other gas codes as well. A forced-vent by itself can pressurize an area around the vent outlet, whereas when it is accompanied by its combustion air intake, the pressures of the two offset each other. One foot is considered sufficient clearance for the gasses to dissipate in the atmosphere just as with a direct vent appliance. Many Category IV appliances can be installed either way. The instructions might allow you to draw combustion air from indoors or from a location remote from the vent termination, in which case the rule for 4 ft. below or to the side will apply. That same appliance might be allowed to have an installation where the combustion air pipe terminates a foot from the vent, and the vent can terminate under a deck or a foot from an openable window. With these appliances, you always need the installation instructions to know if it was installed correctly. Part of the code and the installation instructions is that the instructions must be left with the appliance. A good installer will make some sort of pocket to hold them on the outside of the appliance. At a minimum, they should tape the envelope containing the instructions to the side of the appliance. I've also seen some installers who create a sheet metal pocket to hold the things. I'm told the most common venting defect these days is failing to use the correct primer on the joints of the plastic vent pipes. Douglas Hansen

Chris - I didn't mean to imply that you had recommended he use his friend. I'm sorry to have come off sounding that way. My point was more that it decreases the likelihood of him really finding someone that will be able to tell him any more than what you already told him. Unless your client is in the trades himself, his own personal friends and acquaintances are unlikely to include someone familiar with aluminum wire remedies. It brings up the old question of whether inspectors should give specific answers to the "who can fix this?" question. The "cu/al" designation Jim is referring to was a failed speed bump between devices that were non-specific about conductor material (pre-1970's) and the later "CO/ALR" designation. We do still see "Al/Cu" used on breakers and in panels, but not on switches and receptacles. Thanks Douglas Hansen

allseason: Is the cu to al crimp method the only fix? DH: No - it's a method least likely to afford any improvement. Best are the Alumiconn connectors. allseason: Are some receptacles or fixtures (newer)capable of handling the al? DH: Yes - those which are rated CO/ALR. They are a specialty item seldom found in the real world. Allseaon: The buyers friend is a sparky and he's probaly there already, as I had advised. DH: Advising a sparky and advising the buyer bring in his friend are two separate things, with the latter likely to result in other issues. Please remember when you recommend "further evaluation" by an electrician or electrical contractor that such evaluation is NOT a part of their training. It is part of a home inspector's training. I have run into very few electricians who have the slightest idea what to do with an aluminum wire system, or with most of the problems we find in older equipment. There are some other problems shown in your photo, with the low-hanging fruit being the doubling up of conductors in that terminal bar. The white flecks of material on top of the upper left breaker are also interesting. Is it drywall dust, or is it aluminum oxide that has flaked off and landed there? Hard to say from a photo, and 99% of the time, it is just dust. That 1% of the time that it is aluminum oxide is important. Let's see if client's sparky friend recommends another terminal bar, torquing the connections, and any kind of evaluation of the terminations at the receptacles, switches, and lights. Douglas Hansen

When the ANSI standard for CSST was adopted, it included a provision that the installer was required to complete a certification program. The program isn't much - sitting through a couple hours of training and taking a 25-question open-book test - though it is better than nothing. The product is now being sold in Lowe's, Home Depot, and other big box stores. Purchasers are not asked to demonstrate their qualifications to install it. Douglas Hansen

1918 Douglas Hansen

My understanding of 3-light testers is that each light represents voltage potential between a pair of the receptacle slots. Typically the middle light indicates potential between hot & neutral, the right indicates hot-to-ground, and the left neutral-to-ground. The left light could glow from a receptacle that has a downstream load on the circuit (including a multiwire circuit). The voltage drop on the neutral becomes a potential to the grounding slot, which might be faintly visible, depending upon the sensitivity of the instrument. If all 3 lights were brightly lit, I would discard that theory and pull out the multimeter. I believe the faint light you see on the switched half-hot receptacle is an illusion caused by the proximity of the hot slot to the unswitched hot conductor. Again this would vary depending upon the sensitivity of the instrument. We should always remember the limitations of these devices. If the tester says that all is OK, there are 3 possible scenarios: (1) a false ground, (2) reversed polarity plus a false ground connection between the neutral and grounding terminals, meaning the ground is then hot, and (3) everything actually being OK. It reminds me of why Woody Hayes did not like the forward pass. He said "3 things can happen, and 2 of them are bad." That said, if I were a home inspector I probably would own one of those testers, since they save a lot of time and are suitable for the first pass on most receptacles. I would also carry other instruments to double-check any unusual readings. In my own work I use a TASCO Inspector III, which I find to be very reliable, as well as the usual arsenal of multimeters and non-contact sensors. Douglas Hansen

Though I rarely use a flashlight when taking pictures, I used one here just to highlight the height of the screws. Reuben used the flash on his camera, which tends to flatten the image. Still, I see what you mean. If those screws are loose, they're not loose by much. If it was from a lightning strike, it would had to have been just right - enough to burn the higher-resistance connections, but not high enough to burn the wires themselves. I'd also expect to find similar burning at other connections elsewhere in the system. - Jim Katen, Oregon In Reuben's photo, there are indications of overheating on the equipment grounds and the bonding jumper, perhaps a point for the lightning scenario. There is also a lot of corroded copper, something I wouldn't anticipate from a one-time event, and that would more likely be associated with some long term overheating. Take back that point from the lightning side of the scorecard. It would be interesting to know the history. Douglas Hansen

I wondered about the "all screws loose" scenario too. In Reuben's photo, it looks like the screw heads are recessed to the level they would be if they were tightened. The ones in your photo don't look the same. Douglas Hansen

Could this damage be the result of a lightning strike? Douglas Hansen

I looked into this a while back, and got the idea there should be both types of smoke detectors in every home. Why choose one over the other? The merits of each technology are different. Ionization alarms are supposed to respond more quickly to fast-moving flame, and photoelectric alarms respond more quickly to smoke from smoldering fires. On those points there seems to be universal agreement. Beyond that, the debate becomes passionate. As I understand it, the advantage of ionization alarms is that they respond 30 - 90 seconds faster to a fast-moving flame than a photoelectric. That also means they respond to things that won't set off a photoelectric, such as the smokeless beginnings of my toast getting overdone, or the invisible amount of steam in the hallway from taking a shower with the door open. The title of this thread is based on just such an unwanted alarm activation (probably a better term than "false" alarm, since something did happen to set the thing off). It is also the reason folks are so much more likely to disconnect that type as compared to a photoelectric. On this latter point there is also widespread agreement, including NFPA's white paper on the subject. The advantage of photoelectric alarms is that they respond more quickly to smoke from a smoldering fire. The claim is that they respond 30 to 90 minutes faster. If your furniture is smoldering while you sleep, you won't live 30 to 90 minutes. Some of the stories on the web links posted earlier, such as that from Fathers for Fire Safety, include instances where over a dozen ionization alarms failed to go off until after the victims were dead. NFPA 72 systems (cental station alarms, often linked to fire sprinkler and/or security systems) universally use photoelectric detectors. Commercial smoke detectors are all photoelectric. You can't predict what kind of fire you are going to have in your house. I see it as a choice between one that gives me a 90-second advantage for one type of fire, versus one that gives you a 90-minute advantage over the fire more likely to kill you. So is it an either/or choice? A lot of folks have come to the same conclusion that you did Brandon. Right now, our (California) fire marshal has convened a task force to look into the issue, and I am willing to bet the ranch that they will end up recommending that houses have both types, because that is the only realistic political solution. That doesn't mean it is the "right" solution. A great argument can be made against combination ionization/photoelectric types, since the way that some of them resolve the unwanted tripping issue is to require that both internal detectors be activated, not just one. In other words, they require the worst features of both! Please do look at the 7-minute video posted in my previous message. It questions UL's test method. While I think it is partly an unfair hatchet job on UL, I can't help but think the UL spokesman's position is tantamount to "the operation was a success - so what if the patient died." In fairness to UL, they are not the sole contributors to the standard test procedure. There is plenty of blame to spread around. Did I mention this issue becomes passionate? Douglas Hansen

Back to Pushmatics, after reading over everyone's contribution I think my problems with them really are attibutable to their age more than any other factor, and that seems to vary from one locale to another. The AIC issue shouldn't matter if the panel is a subpanel. If it has a fuse main, the fuse will protect it from high fault currents. That said, I do see a couple of other problems. The picture Les posted is not exactly an argument for the case that these are somehow a more robust design, especially with the holes chewed through the fiberboard dividers. Next is the issue of handle ties. I have seen them on Pushmatics, though I would expect them to be hard to find. They are more likely to be needed now that all multiwire circuits require them. I suppose one could buy a 240-volt pushmatic breaker to get the handle tie, but it seems odd to have to pay $60+ for something that you could do for 60 cents on a modern panel. Jim, be careful. We need you. Douglas Hansen

Thanks John. The article you found does indeed make it sound like there are two sides to the story. It is to be expected considering the hundreds of billions of dollars in lawsuits that the manufacturers are currently facing over wrongful deaths from non-functioning ionization alarms. If you read the article carefully you will see it was based on zero real-world testing. I too used to think a smoke alarm was a smoke alarm, and that it didn't make much difference. I don't believe that now. I will pass the link along to some of the folks who are working on this issue. There are a lot of folks who are more well-informed than me, and perhaps I can get one of them to respond. When I see stuff like this (misinformation that can kill), it is hard not to take it personally. I also try not to take it personally when someone claims that smoking does not cause lung cancer (as a certain MIT scientist claims). The folks who do take it personally are groups like Fathers for Fire Safety, comprised of parents of children who died unnecessarily as a result of non-functioning ionization smoke alarms. http://www.theworldfiresafetyfoundation.org/home.html When I first learned of this issue (quite recently), I checked the alarms in my own house, and discovered that they were ionization types, and that the batteries were missing from 3 of them. One was giving false alarms from my wife's shower, and the other 2 were giving false alarms from our kitchen. Since replacing them with photoelectrics we have had no false alarms. I suggest looking at this link: http://www.theworldfiresafetyfoundation.org/home.html Next you could research it on NFPA's web site, which I have done, and even they grant that there is a much higher incidence of false alarms and disabled alarms with ionization types, along with a much slower response time to real world deadly smoke-producing fires. We tend to place a great deal of faith in things that have a UL label or a CSA label. As someone who has spent a great deal of time involved in the worlds of codes and standards, I can assure you that such faith is badly misplaced. UL's test for smoke alarms consists essentially of throwing the thing in a box along with a smoke bomb. Surprise - ionization alarms pass that test, even though they don't pass the test that counts, when something in your house is producing deadly quantities of smoke. Here is a direct link to the issue of UL's standards: http://theworldfiresafetyfoundation.org/ul I suggest spending 7 minutes watching the video in that link. Douglas Hansen