Douglas Hansen
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Everything posted by Douglas Hansen
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If the gas line is properly bonded, the breaker trips, killing power to the circuit. If the gas line is not bonded, the person touching the gas line and an adjacent grounded surface will become the human bonding jumper, killing the person.
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Marc does have a point here about parallel conductors. If a parallel installation looks too neat, there IS something wrong. In order to get the conductors the same length, it will end up pretty ugly. However, that isn't what we have here. Marc, your numbers would only make sense if the total length of those two pairs of conductors were so different from each other all the way back to the utility transformer. That isn't the case. One of those 2-pole breakers sees X amount of resistance back to the transformer, and the other one sees 99.99% that much resistance. It isn't enough to make a difference. Factory-made quad breaker setups always have these slight differences in conductor length. They wouldn't be listed and labeled if it made a difference. The amount of VD within those final lengths of service conductors are indeed going to be very different; they just still don't amount to nearly enough in such a short distance to have any consequential effect.
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You can go here http://bulk.resource.org/codes.gov/nj_residential.pdf and download a copy of the New Jersey residential code. You will see in the beginning pages of it that no amendments were made to IRC chapter 16, and that the sections you cited do indeed permit class 0 and class 1 ducts. I suggest photographing the "class 1" label and printing out the pages on ducts (chapter 16 is only 4 pages long) and writing a letter stating your case. The city is supposed to have an appeals board for these issues. If they don't, then I would submit it to the city attorney and the town council. If the ducts were class 2 (something that hasn't been placed in houses for over 20 years now) the inspector could legitimately ask to have them replaced. If the ducts were inside an attached garage, he could ask to have that portion within the garage replaced. If there is some other documentable specific failure to comply with the rules in chapter 16, then a correction notice could be issued forcing you to comply with those written rules. It doesn't sound like any of that is the problem, and the real problem is likely to be the one that Bill suspects. You will be doing a favor to your fellow citizens by not knuckling under. Something needs to be brought into compliance in your town, and it isn't your duct system.
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Al branch circuits weren't expected here
Douglas Hansen replied to John Kogel's topic in Electrical Forum
We had a very similar aluminum cable in the mid-1960's that was made by Kaiser. The outer sheathing was a plasticized fiber of some sort, kind of a stepping stone between the old rag-wrap copper NM and the PVC sheathing of the late 60s. -
Yes. You're right. Since, in this case, the neutral is not switched, the generator is not considered a separately derived system and the the ground/neutral connection should only be present at the service panel (or before it). Aside from adding an equipment ground bar to this subpanel, the bonding jumper must also be removed inside the generator, otherwise you will still have the problem of a connection between the neutrals and equipment grounds past the service.
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408.40 in the NEC requires a terminal bar for the equipment grounding conductors. The panel manufacturers do not always supply a separate equipment ground bar, since the same panel might be used as service equipment where the equipment grounds and neutrals could go on the same bar. They do make separate terminal bars that are easily added to a panel like this one. While it is not likely to have any effect on the electrical performance of this piece of equipment, allowing a thing like this to pass is the first step on a slippery slope. It is the signature of someone who did not know how to wire a panel. It should be corrected by a real electrician.
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Could the wires to that receptacle also be in a channel inside the baseboard?
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Steel Building-Lighting Rods?
Douglas Hansen replied to Steven Hockstein's topic in Electrical Forum
Franklin systems have propagated since 1752 because they work. UL 96 provides listing for components of lightning protection system, and NFPA 780 provides installation guidelines. NFPA 780 is dealing essentially with passive lightning protection using the principles espoused by Franklin. Early streamer emission and dissipation array systems have been attempted and have no real record of success, whereas passive protection has worked for a long time. Lightning is an alternating current that travels in steps, in both directions from earth to sky and back. The placement of air terminals per NFPA 780 is intended to provide an umbrella of protection. It uses a "rolling sphere" model for this, where air terminals on top of a building are of sufficient height such that a sphere with a 150 foot radius would roll over the terminals without touching the building. By placing them at those intervals, the "step" of the lightning strike would reach a terminal before it would reach the building structure. While some aspects of lightning protection are understandable, there are also things like ball lightning that defy explanation. NFPA 780 has an interesting disclaimer: "Lightning is a stochastic, if not capricious, natural process. Its behavior is not yet completely understood. This standard is intended to provide requirements, within the limits of the current state of knowledge, for the installation of those lightning protection systems covered by the standard." -
Request for Critique
Douglas Hansen replied to Jim Katen's topic in Report Writing and the Written Word
I think WJ once described these sorts of documents as a puzzle rather than a report. I find that attempting to sort it out is painful. The information is consistently cloaked behind the attempt to first characterize its significance, or lack of same. I would not be pleased if I were a client and got this in return for my money. If the unique definition of a GFCI didn't disappoint me sufficiently, the advice to "Buy an old crescent wrench at a garage sale" certainly did the trick. -
Inspection World
Douglas Hansen replied to allseason's topic in Professional Home Inspection Associations
Yep - I'm on the menu. -
The codes mention roofing nails and a requirement that they comply with ASTM F1667 (which also includes some staples). If the roofing manufacturer wants to have staples approved under the provisions for Alternative Materials, Design, and Methods, they can do so by obtaining an ICC Evaluation Service Report. If you look on GAF's web site, they will tell you they don't ever recommend staples. Then if you look here http://www.gaf.com/Roofing/Residential/ ... 321-v4.pdf you will find an ICC ES report that does allow staples for that very manufacturer's product. Most of the problems with staples are the result of poor installation. If someone takes the time to get the staples in the correct orientation, in the proper nailing zone, and sets the pressure properly, they can be OK. Odds are you will find lots of other problems with their placement, not just the fact that they are staples.
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Shameless Request
Douglas Hansen replied to randynavarro's topic in Computers & Reporting Systems Forum
We are very happy with Dropbox. 1st couple GB are free. I think I pay $100 a year for 50 GB. -
The rule on protection where entering a panel was new to article 312 in 2002. It is a very specific case that is an exception to the basic rule that each cable be secured to the panel. NM cable and other types of cable are allowed to be pulled through raceways as long as they meet the fill requirements. You could pull romex through EMT all through your house if you were so inclined. It isn't prohibited by the rules for NM or for EMT. Note 9 to Table 1 in chapter 9 tells us to count the multiconductor cable as a single conductor for fill purposes (not for derating) and to use the long dimension on elliptical cables.
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I converted to pre-twisting about 3 years ago, except when connecting stranded to solid. I grab the ends of the wires with the sidecutters, twist, and cut off the end tails. Then I add the wire nut, and twist it by hand until the insulated portions of the wire also show a twist. When connecting stranded to solid, I lead the stranded a bit longer and allow the wire nut to do the twisting. When using a tool to twist the wire nut, it is really easy to overdo it and drive the wire right through the end of the plastic.
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Since 1/1/11, California uses a residential code based upon chapters 1 - 10 of the IRC. The Building Standards Commission publishes a free training guide explaining California's codes: http://www.documents.dgs.ca.gov/bsc/Tit ... gGuide.pdf
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My house in Palo Alto had one of these, a recessed laundry room subpanel. One of the breakers wouldn't reset, and someone had double-tapped another breaker to keep things going. After I moved in, another double-tapped breaker failed, so I replaced it with a new surface mounted box over the old one, pulling the wires into the back of my new one. The house was built in 1938. I was a bit surprised that it had breakers at that age. The main outside and the other outside circuits were fuses.
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Smart Meters are a very emotional issue in this part of the world. PG&E (our local utility, and an acronym for "Pigs, Greed & Extortion") has not exactly been forthcoming about why these things are so necessary. The idea that they will enable real-time monitoring of power consumption to more efficiently manage the grid is nonsense. First off, most substations don't have automatic tap-switching to regulate current flow on the line. Next, even if they did implement automatic tap-switching, the only data they need could come from one device at the end of each line, not a smart meter on everyone's house. PG&E is the company that brought us the San Bruno gas explosion, among numerous other tragedies, and pretty much behaves like the poster child for corporate irresponsibility. What most folks are freaked out about here is the potential health issues from yet another radio transmitter, one close to the frequency range of cell phones, short wave, etc. PG&E strong-armed their way past any open discussion of the issue, branding anyone that failed to trust them as a kook. When they started installing smart meters in Marin County, citizens would form human barriers and blockade their trucks from entering rural property (they started in the western part of the county). As a result, the first meters were put in literally at the point of a gun. Every governmental jurisdiction in Marin County issued a moratorium on installing more smart meters, and PG&E responded by saying they were not subject to local laws. My local state congressman (Jared Huffman) put in some legislation requiring PG&E to hold off and allow more studies and to allow folks to opt out. After Huffman's legislation was introduced (and before it was passed), they offered to allow us to opt out for a $300 opt-out fee, a $30 a month meter-reading fee, and a $300 end fee. They said this was necessary to recover their investment in Smart Meters. That plan too was quashed thanks to public outrage (the one thing PG&E is still capable of generating). In the meantime, PG&E spent $65 million on a statewide ballot initiative to prevent local groups from forming energy cooperatives, such as the Marin Energy Authority, which will be replacing many of PG&E?s functions in our area. PG&E's initiative lost at the polls, despite outspending the opponents by a drastic margin. In case anyone is curious, here is a white paper from the company that manufactures the smart meters that PG&E uses: http://www.silverspringnet.com/pdfs/Sil ... -Final.pdf They claim these things work much better on an unlicensed spectrum. Why am I not reassured? So back to the point. I called up PG&E a few months ago and asked them if they knew anything about smart meters interfering with AFCIs. To my surprise, they said yes, and that they had "2 kinds of smart meters, including one that didn't interfere with AFCIs." I asked them what I would have to do to assure that I got that type, and they said they didn't know and would call back. They never did. As part of my participation in the local IAEI chapter, I interact with PG&E's representative pretty routinely. He knows NOTHING about smart meters and AFCIs. He also didn't know there were two kinds of smart meters. The same is unfortunately true for some of the other smaller municipal-owned utilities in our area. Maybe there really aren't two kinds, and it is just something that PG&E's flacks have been trained to say to people like me. Bottom line, I don't know if these will cause a problem with AFCIs. There are many reports of the first ones causing nuisance tripping in houses in San Jose. My hunch is that the problem is going to be found on the older branch-feeder AFCIs, since they seem so inferior in other regards to the newer "combination" AFCIs, but who knows? The only thing of which I am certain is that PG&E is not telling us the truth on multiple levels.
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Need advice on 200 amp underground service
Douglas Hansen replied to Firestarter's topic in Electrical Forum
Hi Robert First off I applaud you for doing some checking before attempting something for the first time. I do wonder if you came to the best place for that. This forum is used primarily by inspectors, and not by electricians or DIYs. There are several excellent electrical forums out there, including Mike Holt's forum, where you can expect to hear a lot more on this question. http://forums.mikeholt.com/ My first question would be why you are bringing this underground. We normally see that only with pad-mounted transformers, not overhead conductors, though I'm sure you must have a reason. Next, the 2 inch conduit would meet the code for your 4/0 wires, but it may have to also comply with utility rules. Here in my part of California, our utility has a minimum 3-inch size for all underground services. Also remember that your 2 feet underground means 2 feet of cover on top of the conduit, not 2 feet from grade to the bottom of the ditch. If you're going to use 4AWG copper to your ground rods, you don't need conduit for them. You could use 6AWG (even though you have a 200-amp service, grounding electrode conductors that solely serve rods never have to be larger than 6). You still would not need conduit if you ran the conductors onto your posts or strapped to your riser. You may need expansion fittings on the pole, though most likely that can be avoided with straps that allow some movement. Depending on the slope of the grade and the potential for frost heave, you may need a meter riser slip fitting. I'm not impressed with that Milbank equipment. Siemens/Murray make some nice meter mains with a separate pull compartment to the left of the breaker compartment. Finally, your rods will have greater efficiency if they are further apart. 6 feet is the code minimum. 16 feet would be better. I think you want to do some research with the local utility and building department before proceding. Good luck. -
Am I seeing this correctly that another pipe enters from the background of the picture, and that there is no vertical vent pipe at the sanitary tee that is just downstream of the wye with the shower trap arm? Regardless, this thing is a mess. If that pipe to the right is the vent, then the problem with having it "flat vented" is that water in the shower arm can close off the vent, siphoning the shower trap. Anything that causes you to lose a trap seal can allow entry of sewer gases, vermin, and other nasties into the living space. If that pipe to the right is a fixture drain with a vent on top of it, then you conceivably have an instance of horizontal wet venting, which California started to allow in bathrooms in 2008, except that it is still fubar. The wet vent would need to be sized for all the fixtures for which it is providing venting, and it doesn't seem possible here. The sanitary tee also has to be vertical. What is the other pipe coming in through the combo fitting in the foreground? It also looks like they notched the bottom of the beam. A sort of general rule to follow on something like this is that plumbers will install pipes vertically or horizontally. They won't improvise something that is in between.
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I've seen a few built-in vacuums that required a 30-amp / 120-volt circuit. Obviously a different situation than your 3-bedroom duplex.
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Wouldn't that cause the service mast to act as a parallel conductor to the neutral? That seems like a bad idea. No? If not, then why the insulator? It would cause the service mast to act in parallel with the neutral. I don't see that as a bad idea. It would have current on it. It would have only barely measurable voltage. The NEC allows the neutral to be a bare (copper) conductor inside that service riser (230.41Exc.1). A bare neutral would also allow current on the service riser. We've already seen what happens in a fault situation with the bonding jumper missing. So, let's look at what happens in a no-fault situation: Suppose you have 2AWG aluminum service conductors and service drop conductors. To give us some measurable voltage on them, let's say the service drop is 100 feet back to the transformer, and that we have 10 feet of 2-inch steel conduit between the service equipment and the weatherhead. Next let's assume a really huge imbalanced load, like maybe 60 amps, which is more than you would ever see in real life. The voltage drop on the service conductors would be approximately 2 volts (60 amps times 0.0319 ohms). In the first 10 feet of that, the voltage drop would be 0.2 volts. That would be your maximum theoretical voltage potential between the service neutral and the mast at the top. In practice it would be much much less. There isn't a need to insulate it to try to maintain voltage potential between them. Again, I think the insulator is someone's idea of a mechanically more reliable connection. In the same vein, the service enclosure also carries a small amount of current, yet if everything is connected right it is safe for you to touch it. It and the grounding electrode conductor are in parallel with the service neutral. Jerry Simon has taken many pictures of his ammeter clamped around the grounding electrode conductor and showing fairly high amperages. Those grounding electrode conductors can show that kind of current while still having barely measurable voltage. Same story here at the weatherhead.
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Can you tell us why? It's never done that way in my area. The neutral must always be bonded to that mast. The place where you typically see that bonding connection is in the service equipment, and any additional bonding at the point of attachment should only be adding to what was already present. Using an insulator at the mast may provide a more reliable or durable connection from a mechanical standpoint, but not electrically. Suppose that inside the mast the insulation on a hot conductor is damaged and that it energizes the conduit. The path for current is from the conduit to the enclosure of the service equipment, across the main bonding jumper, and over to the incoming service neutral. There is no breaker in that circuit - it is on the "line" side of the service equipment. A fault as described here is going to cause something pretty bad - it could possibly cause a fire or blow up the utility transformer. If you were lucky it would trip the overcurrent protection on the primary of the transformer and just knock out power to all the customers served by it. Suppose we have the exact same thing, only this time there is no main bonding jumper in the service panel. Now nothing blows up. Instead, something much worse happens. The conduit sits there with 120-volts potential, waiting for you to touch it while also contacting a grounded surface. You become a human bonding jumper. If the service mast had been anchored with metal to metal contact instead of that insulator, we are back to plan "A" (a noticeable fire or explosion instead of a potential electrocution). The reason we require bonding jumpers around concentric knockouts on the line side of the service is to assure that we are using plan "A" rather than the human bonding jumper.
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Generator Question for sparkys
Douglas Hansen replied to Steven Hockstein's topic in Electrical Forum
I'm not sure what you mean here. To "close" the main breaker is to turn it on, i.e., to close the contacts. To add to Mr. Kogel's point, when we write instructions on these things it is easy for us to use a vernacular that only makes sense to the person that wrote it, and which could mean the opposite to the next person to come along. Nothing takes the place of a transfer switch that breaks contact with one power source before making contact with the other power source. Even with that idea in place, I once ran across a house that had a subpanel that was supplied through an automatic transfer switch that allowed a unique problem. The homeowners were experiencing lots of failures of electronics. They had frequent utility outages and their generator was used a lot. After much effort, we eventually discovered that the hot wire of one circuit from the subpanel was also connected to a circuit from a panel that was supplied only by the utility. When the power would go out, that circuit was backfeeding half of the house off the generator. When the generator would come back on, the transfer switch waits for five minutes of proven uninterrupted utility power before handing it back to them. During those five minutes, half the house was receiving power from two independent out-of-synch 60-herz sources, resulting in electronic mayhem. Blocking diodes in the generator are supposed to prevent this, but they didn't. Some 30K later, we ended up putting the whole house on the generator on a new transfer switch. -
Generator Question for sparkys
Douglas Hansen replied to Steven Hockstein's topic in Electrical Forum
I agree with Marc. Instead of creating a cord with suicide plugs on each end, buy a small Generac transfer switch and have it installed by an electrician. It is pretty simple. You place it next to your panel. A whip runs from the transfer switch panel to your existing panel. Inside the whip are wires for a half-dozen circuits. In your panel, the conductors to those circuits are intercepted and run to the transfer switch panel, and other conductors in that same whip make the connection back from the transfer switch to your breakers. The transfer switch plugs into your generator. -
The SWD rating is an additional (and pretty meaningless) designation. It can also be used as a switch for other purposes, such as incandescent lighting. I think the idea is that an older magnetic-ballast fluorescent has a greater initial current surge, and the SWD rating means that UL has evaluated it for a certain number of such operations without degradation of the internal contacts.
