Douglas Hansen

I don't think the TASCO is designed to detect bootleg grounds, though it does give a very precise (hundredth's of an ohm) readout of ground impedance. I understand the importance of discovering that condition in a home inspection. When I was a home inspector, I found it could always be deduced from other indications. If the wiring in the panel was two-wire rag-wrap Romex, and the receptacles tested as having proper grounding, then something wasn't making sense and I would start taking off cover plates to get a closer look. In the type of work I do today the "false ground" problem is never the issue. The TASCO indicates voltage drop overall, as well as individually - the amount on the hot conductor and the amount on the neutral. It indicates true RMS voltage, and more amazingly, it indicates the available short circuit current, both on a hot-to-neutral fault and a hot-to-ground fault. The numbers are very accurate. Douglas Hansen

I own a couple of Sure-Test tools, including their very first model. I found them always a bit too quirky, and I greatly prefer the TASCO Inspector III: http://www.tasco-usa.com/inspectorIII.htm I have done two extensive "before and after" mappings of very large houses with this tool, each involving over 200 receptacles per house. The tool was invaluable, and on one house we were able to salvage a system that might otherwise have required a complete rewire and repairs in the high six figures. This tool can tell the difference in quality obtained from a pre-twist splice made and one made by letting the wire nut twist the wires together. I have used it in other forensic work, and it is highly accurate and very reliable. I could seldom get the same result twice with a SureTest, and would never dream of going back to one of those. The specs and instructions for the Amprobe INSP-3 look remarkably similar, though I have never seen one of those. Douglas Hansen

Is this a builder that always builds things to the dead minimum requirement? If so, a couple things could be going on. The designer and/or plan reviewer may have misinterpreted the code section (even though the exception doesn't mention showers), or there is another window someplace that is the same size and was supposed to be tempered. I've seen a few times where the windows were set in the wrong location, and this is a fairly likely wrong location. Marc - the code section speaks for itself. I think the trap in reading it is to think the converse of the exception must be the rule, i.e., to think that since glazing more than 60 inches away from a tub never has to be safety glass, then glazing closer than that is always required to be safety glass, even though the rule preceding the exception doesn't say that. In the NFPA Manual of Style, there is a strong push to eliminate code language that contains exceptions, precisely because they lend themselves to misinterpretation; people read implications or hierarchies into them that are not really intended. I wish ICC would to the same. Douglas Hansen

For questions like this, it is possible sometimes to find the answer on ICC's web site. At this address: http://www.iccsafe.org/cs/codes/Pages/0 ... anges.aspx one can find the file with the February 2008 proposed changes to the IRC. The idea of re-wording the sections on safety glazing was proposed by Rick Davidson, City of Maple Grove, MN, representing the Association of Minnesota Building Officials. Mr. Davidson said the following about his overall proposal to reword these sections (commenting here on the 2006 IRC): "This is one of the more difficult and confusing sections of the IRC to use. Exceptions to the rules are not listed after the rule but following the entire section where they can be overlooked. Furthermore, it is necessary to read through all of the exceptions to find any that might apply to the rule being used. There are conflicting rules where one rule will require one dimension and another rule requires a different dimension. Measuring locations vary even within the same rule. And some rules are exempted in every application making them always moot. The modifications found herein are intended to be largely editorial. They are intended to relocate the exception beneath the applicable rule, eliminate unnecessary language, and eliminate conflicts. Also please note that numbering of the items has been changed so that similar rules are grouped together. Following is a point by point explanation of what is proposed." He then went on to list the specific proposed changes, including the one that has the current 2009 IRC language. Regarding that specific new wording, he also said: This section includes a new exception to address the matter of hot tubs, whirlpools, or bathtubs adjacent or near windows but not in an “enclosureâ€

The latest news on this topic casts quite a different light on it. It seems the question isn't what sort of feel-good bonding to apply, but whether the stuff should be allowed at all. Could this be the end of CSST? Douglas Hansen Download Attachment: CSST_Product_Liability_Suit.pdf 567.68 KB

Thanks guys. One of the San Francisco inspectors said the same thing too. Douglas

In our discussion group here in the Bay Area, we are scratching our heads over this photo taken in a 100-year old house. I'm guessing it is a tempering tank. Anyone familiar with these? Douglas Hansen Click to Enlarge 86.38 KB

I've heard of significant savings by adding VFDs to pumps for pipelines. I'm supposing that the advantage is to maintain torque while being capable of varying the speed. Within a facility the situation is different; the addition of VFDs might require isolation transformers & K-rated transformers to prevent harmonics from coming back into the power system. These could add to the installation cost, and their energy losses could partially offset the savings of the VFDs. I suggest consulting a qualified power quality engineer. Douglas Hansen

Michael - I think the "old school" electrician is demonstrating that grounding and bonding remain the most misunderstood of subjects, even among veteran electricians. As Tom said, the masonry wall could become a good enough conductor to help give you a jolt, though that has nothing to do with creating a fault return path. Earth is never an equipment grounding conductor. It can't be relied upon to carry enough current to trip a breaker, but it can carry enough current to kill you. One possible way that an industrial electrician could be confused upon this point is that a concrete or masonry surface is considered a "grounded" surface for purposes of required clearances opposite live parts of electrical equipment (110.26 in the NEC). In that sense "grounded" is not synonymous with "effective fault return path." I see it as one more unfortunate example that the NEC's poor choice of words has led to. We say "ground" when we mean earth, and we say "ground" when we mean bond. Jim - my experience with this is that pre-1960's romex didn't have equipment grounding conductors. When romex started to show up with an equipment grounding conductor, electricians weren't always sure what to do with it. Here in California, the 1962 NEC requirement for grounding-type receptacles sometimes wasn't enforced until 5 or 6 years later, but the romex from the supply house had a grounding conductor by 1962. Since the old "nail to nail" method had been to put the grounds on the outside of the box, that is what electricians did with it. I know of some jurisdictions that even required it to be that way, though eventually the NEC made it crystal clear that the grounds get made up inside the box. There was a short period of time there - about 6 years - when those equipment grounds were also a smaller gauge - 16AWG on 12AWG cable, and 18AWG on 14AWG cable. Douglas Hansen

Prior to the use of plastic or bakelite boxes, it was pretty common to see metal boxes grounded by some other means than the wiring method. Since at least 1923, the NEC required all metal boxes to be grounded, then gave exemptions for those which had some requisite distances from other grounded objects. The net effect of the rule - at least around here - was to find that the boxes in bathrooms, kitchens, laundry rooms, and some exterior locations would be "grounded." Woody and I like to refer to this method as "nail to nail" grounding, since it typically involved whatever wire was handy being looped around the box mounting nails, then eventually being wrapped or clamped to a water pipe. It does seem likely there would be regional variations on this theme. It did still take place in the 1950's with rag-wrap romex. It raises interesting questions for code compliance. Whenever we replace a receptacle in a location where a grounding means exists, we are supposed to use a grounding type receptacle and utilize that grounding means. Ordinary receptacles don't quite qualify, since the mounting screws are not intended as a grounding means unless they are "self grounding" receptacles with one screw captive in a metal washer secured to the yoke. The other side we could question is whether that grounding means is really effective. It isn't going to be the low-impedance path or the method that would be used today, though it is better than nothing. Click to Enlarge 35.24 KB Download Attachment: 250G-130c_N2H2o.jpg 153.28 KB Download Attachment: 250G-130cNtoN.jpg 201.02 KB

It makes just as much sense to think that you reduce the chances of lightning damage by throwing salt over your left shoulder when the moon enters Aquarius. Bill quoted the engineer at the source of this misinformation as having written: "Electrical Bonding and Grounding, has been revised to require that all CSST systems be bonded to the electrical service ground where the gas service enters the building using at least a 6 AWG copper conductor or equivalent. This bond is intended to divert much of the lightning energy directly to earth before it can jump to another nearby electrically conductive pathway, such as copper water pipe or electrical wiring". There is so much to pick apart in that last sentence I hardly know where to begin. First, "lightning energy" rises from the earth as much as it goes down to it - it's an AC current that pulses. Second, the "water pipe or electrical wiring" are also supposed to be bonded. Elevated voltage through the structure from a lightning strike affects all conductive materials. The water piping and electrical wiring already have the "lightning energy" on them. The author wants us to believe that lightning is going to somehow reach earth through the CSST bond before (his word) that lightning reaches the earth through the even better path of the electrical wiring. Where do we get such men? Lightning protection systems operate on the principle of creating an umbrella around a structure. The idea that somehow lightning is going to be controlled (or that damage from lightning can be predictably minimized) by taking it through ONE of the metal systems in the building and bonding it differently than the others, while separating it from the others, is pure hokum. That is why the electrical code treats bonding of these systems from the viewpoint of shock hazards and clearing faults, and NOT from the standpoint of lightning protection. One of the original Texas CSST lightning fires happened from a lightning strike on a metal chimney. There was CSST to the fireplace connected to that chimney. The chimney acted quite predictably as the lightning rod for the building. If they wanted to protect the gas piping, the way to do it would be to ground the chimney. It worked for Franklin; it still works. John, I think you have been victimized by the self-serving PR of the manufacturers and their interest in finding simple ways to reassure the public that their product is safe. It always was, but reality becomes irrelevant when the lawyers step in and file class action suits based on a statistically meaningless anomaly. If I was a CSST manufacturer, I don't think I could stand up and say the emporer has no clothes. It would be much easier to recommend a harmless bonding conductor. Douglas Hansen

A dissenting viewpoint: Bonding of CSST is a solution in search of a problem. Thanks John for posting those links. They are informative, though I do not think of them as authoritative. The NFPA annual report on lightning tells us that we have some 4800 house fires a year as a result of lightning. We have now 4 documented cases of CSST contributing to those lightning fires. Something doesn't make sense. When the second CSST lightning fire occurred the class action suit was born. The settlement of same never did result in monetary awards - other than to pay the cost for installers to bond it in the manner that had already been required by code. The purpose of bonding gas piping in the NEC is to create a fault return path and to eliminate voltage potential between metal surfaces. It has nothing to do with lightning. The gas industry historically has had a prejudice against bonding of their piping, in part because of very real dangers that arise from static electricity while working on open pressurized underground gas lines. I don't mean any offense to them, but they have also repeatedly demonstrated an historical lack of understanding of electricity. I once heard the head of a major utility's gas division proudly announce that they were prohibiting the bonding of their gas piping - and would remove the meter from a house - if the piping were bonded in any such manner that current could flow on it. He seemed to think that bonding gas piping would put voltage on it. It does the opposite. It helps clear a fault to get it off the gas piping. Current only flows on conductors in the presence of a difference of voltage. Voltage potential between any two metal surfaces is a hazard, all the more so when one of them is gas piping. Maintaining a separation between items such as gas pipe and metal ducts, only to later bond them together to the same grounding target at the service, is just plain silly, but it plays well to the gas industry. The motivation behind the CSST industry's initial response (when they were requiring the 8AWG bonding at the manifold) was a way to say "we've done something - we've solved whatever problem we had." Likewise, the current IFGC, IRC, UMC, UPC, NFGC requirement for the 6AWG bonding conductor on the hard piping upstream from the CSST is the result of the industry convincing the authors of the gas codes to play along in this feel-good campaign. The CSST industry was not successful in getting this into the NEC, and I doubt they ever will be. The folks on CMP-5 (those responsible for article 250) actually understand electricity, grounding, and bonding. They will allow bonding as the manufacturers requested, because it is doing no harm. They will not buy into the mistaken notion that this new particular method is somehow an improvement. Their language in rejecting the proposal was as follows: Panel Statement: CMP-5 is not convinced that bonding to or around portions of CSST will solve the problem. No test records were provided to substantiate the adequacy of the minimum 6 AWG conductor. The problem could be directly related to the design and wall thickness of CSST. CMP 5 was made aware of at least one manufacturer’s product that does not require bonding beyond the requirements of Section 250.104 contrary to the information provided in the substantiation. The mitigation of the effects of lightning is a design option. The purpose of the NEC is the practical safeguarding of persons and property from hazards arising from the use of electricity. The recommendation is not currently prohibited by the NEC and should be covered by product standards. NFPA 54 contains bonding requirements specific to this product, and those requirements do not conflict with the NEC requirements in Section 250.104(B). To me bonding of CSST is just another in a long line of useless rules that we are saddled with due to the politics and semantics of codes, without any basis in reality. I'm sure we can all think of others. Several examples come to mind. Start with bonding hydromassage tubs. The NEC made an awkward attempt to outlaw "dummy" grounding terminals on double-insulated pump motors (those without a grounding conductor) in the 1999 NEC. Because it was a last minute insertion by the CMP, and not a public proposal, their poor wording made its way into the code, and was revised in each of the subsequent four editions in an attempt to conform to some reality while also saving face. No one has ever been electrocuted in one of these things, and the bonding is redundant to the grounding and to the GFCI requirements. Yet how many times have I seen home inspection reports that make a big deal of this phantom defect? Another one is AFCIs in bedrooms. No one ever made an NEC proposal to place them just in bedrooms. The floor debate back in the 1998 NFPA conference was for all or nothing. The idea of bedrooms came along at the last second as a compromise - a way to get the camel's nose under the edge of the tent. Yet how many home inspectors act as if these rooms were somehow more important than other areas of the house? It looks silly now that bedrooms are no longer the only area targeted for these devices. The list goes on. Why 25 ohms resistance for the grounding electrode? In earthquake country, flexible gas connectors are the norm, and they are nowhere near as robust as CSST. They have been around a lot longer also. Don't tell the lawyers. Douglas Hansen

The required standard in North America is for the utility to supply voltage to us within 5% of 120/240 volts. If the utility provides a consistent overvoltage or undervoltage the customer's equipment can be damaged, and they try pretty hard to keep it at 120/240. It's becoming more difficult with all the other sources feeding into local grids. In the early (Edison) days of electricity, voltage was 110 and 220 DC. AC systems were designed to match that voltage. (Though AC systems have peak voltages that are higher than the nominal voltage, their net effect in terms of heating up the wire is the same as the nominal DC voltage.) In the 1930's the electrical code changed to 115 and 230. Even today, those ratings are used in the NEC for horsepower calculations for NEMA motors. In the NEC, the change from 115 to 120 was in the 1984 edition, in conformity with the ANSI standard of 120 & 240. Here's a link with more info: http://powerstandards.com/tutorials/Vol ... lation.htm Douglas Hansen

A home inspector in Las Vegas died on the job in July 2004 in a hot attic. He was a highly qualified, well-trained, and sober person, in good physical shape in his late 30's. The last photo on his camera was the one he took from the attic entrance. It appears that he fainted from the heat when he first stood up inside the attic, fell backwards, and landed on his head on the garage slab. He was alone at the inspection. The company that employed him holds weekly safety meetings, and after the accident, they changed their policy on attic inspections. Be careful out there... Douglas Hansen

After seeing the high-rez photo (thank you Michael), I sure don’t see a bonding jumper. There also should have been a grounding locknut on the service entrance conductor conduit fitting. There is a bare grounding conductor from the transfer switch to the panel. It is connected to a single lug at the bottom of the panel. There should have been an equipment ground bar in that location, as shown in Generac’s diagrams. It needs to have empty terminals to receive the grounding conductors of the generator feed and the control circuit. When all is said and done, I’ll bet you find out the electrical contractor is someone who does very high quality work, and that he had never installed a transfer switch before this one. Douglas Hansen

There is no generator. You would see the control wires and feeder conductors in your third picture, and they aren't there. Go back to the link Richard posted, and this time paste 0049451 into the search box. You will get a slightly different manual, one that matches this equipment exactly. I can't be sure from the photo, but it looks like the bonding jumper is missing at the neutral bus. I suggest you call the Generac folks and ask them about this setup. It appears their equipment is suitable for use as service equipment. I would be curious what they have to say about installing two of them on one generator. In a typical generator setup, the person who first turns it on is the installer of the transfer switch or a factory rep. The more complicated ones will have a lot of dip switches that must be set, and they want to program the timer for periodic startup and run it through its other tests. One last note - even for large houses like this, a typical generator setup will be no more than 100 amps, if that. You don't expect to be able to operate everything; you do expect seamless transfer of power. Douglas Hansen

I think someone wanted to have an option to add a generator at some later date, and used these ATSs as service disconnects. Considering the difficulty in removing the covers, it seems like a very bad idea. There would need to be two generators with this setup. You can't have more than one ATS on each generator. Each ATS includes sensing circuits that periodically start the generator. In a utility outage, the ATS waits for the utility to prove power before transferring back from the generators to the utility. You can't have two sets of controls doing those things to one generator. Having two generators is also a bad idea. If there is any cross-connection - even of the neutrals - between those panels supplied by separate generators, you can end up with some bizarre voltages and frequencies that will damage consumer electronic equipment. A much better setup would have been to install a 4-pole transfer switch. Then it could be done with a single generator. 4-pole transfer switches are normally for 3-phase systems where the neutral is also switched, but they work fine in this application, with 2 pairs of hot conductors and the neutral not switched. Richards links to the installation manual are very helpful. It's too bad you weren't able to open these up. I wouldn't be entirely confident that all the parts shown in the manuals are actually there until I saw them. I would have some concerns about the grounding of the ATSs. It is OK to have the grounding electrode conductor originate at the meter, upstream of these things, but I would try to find it. Next, the manual states that these things meet CSA requirements as "suitable for use as service equipment." To be approved for use in the U.S., they should be marked "suitable as service equipment" somewhere inside. If they are going to install a generator, they should replace these ATSs with a 4-pole type. If they aren't going to install a generator, they should ditch these ATSs and replace them with a service enclosure that is easily operable. Douglas Hansen

I don't think Texas can take "credit" for this poor practice; it seems to be fairly universal. For many years, the NEC didn't require that each cable be secured to the cabinet. The only concerns were that openings for conductors be effectively closed, and that knob & tube conductors be protected with loom. To avoid heating by inductive reactance, it was important that all of the conductors of a knob & tube circuit enter through the same hole. That practice of running two or three loom-covered conductors through the same hole, with no clamping, may have been the practice that later was applied to NM cables. The rule requiring each cable to be secured to the cabinet began (like so many other rules) with the 1975 edition of the NEC. Since the concern with bundling them is the violation of 312.5©, i.e., not securing them to the panel enclosure, I don't think that any great harm is likely for a completed installation. Is someone going to try withdrawing one cable from the bundle and cause problems to the rest? How much benefit will there be to calling this defect every time you see it? I think it is one that an AHJ should call on rough inspection, because it is still possible to fix it then. For a completed installation, there isn't much to be gained. As to the heat or derating issue, they get a pass on that for bundles less than 24 inches in length per 310.15(B)(2)(a) and also by note 4 to table 1 in Chapter 9: "Where conduit or tubing nipples having a maximum length not to exceed 600 mm (24 in.) are installed between boxes, cabinets, and similar enclosures, the nipples shall be permitted to be filled to 60 percent of their total cross-sectional area, and 310.15(B)(2)(a) adjustment factors need not apply to this condition." Douglas Hansen

First, I assume there is a disconnect in the exterior service panel, above the area in the photograph. You are technically correct, and can add 250.142(B) to your list of code violations on this setup. However, it poses no danger (this time). Current will travel on the neutral conductor between the panels. Because the neutral is bonded, there is also a path for current on the bare grounding conductor. If there is a metal chase nipple between the two panels, there could also be current on that metal. So we have to ask, how much current, at what voltage, and is it a danger? The amount of current intended for the neutral feeder is equal to the load imbalance between the two hot conductors. The voltage on that neutral, at the point where originates in the subpanel, is going to equal the voltage drop from there to the utility transformer, and (absent loose connections) is going to be very low (probably less than one volt). The grounding conductor and the metal enclosures are now going to carry some of that current, but there isn't ever going to be enough voltage potential between the two enclosures for that to cause a problem. It will be so low as to not be measurable with normal test equipment. The further a subpanel is from the service, the more hazards you can introduce by re-bonding the neutral. It might be possible to have current traveling on water piping or other things not intended for current, and the voltage drop on the neutral can sometimes be great enough for the voltage differences to be perceptible. When panels are back-to-back like this, the code is still the same, but the dangers are so low that it is common to have folks like your state inspector signing it off. Home inspectors must pick their battles. A better one to pick here is the violation of 408.41, where the neutral conductors are sharing terminals with grounding conductors. At least that is what I think I'm seeing in the third photo. I see you are not a frequent poster here. This forum has technical moderators who are experts in their subject matter, and the one for this section is Jim Katen. I am only answering this because he seems to be engaged elsewhere this evening, and your message implied that you needed an immediate answer. Welcome to TIJ. Douglas Hansen

Agreed Jim. Even though these things are more efficient and generally lower wattage today than they were 50 years ago, most will exceed 7.2kW. Freestanding electric ranges of that era typically came with a 50-amp NEMA plug. It's interesting to me that ranges have such a high rating, where the combined rating of an individual counter-mounted cooktop and a wall oven might not add up to anything close to that amount, even with greater cooking capacity. I think Brandon nailed it though - what matters is the rating on this particular one. It's not the sort of information I expect most home inspectors look at. When I was a home inspector, I bought one where the homeowner had replaced a single oven with a double oven on a 30-amp circuit, and the circuit couldn't handle both being on at the same time. It taught me to look at the nameplates. Douglas Hansen

I'm not sure I understand the concern on the range circuit. The way I'm reading it, you only need 8AWG for a range circuit that is 8.75kW or greater. If the nameplate of the range is less than that, you need only match the load. I'm looking at 210-10(b) in the 1959 NEC, and 210.19(A)(3) in the 2008 NEC. In the 1959 NEC, the fine print note to 220-4(i) recommends you use table 220-5 for the calculation on the feeder load even if you are using a smaller range, just in case you later replace it with a larger one. However, that has to do with the feeder load calculation, not the branch circuit size. Likewise, note 5 to table 220-5 says you "may" use table 220-5 to calculate the load for a single range. What that means is you can apply the demand factors of 220-5 for ranges in the 8 to 12 kW size range. Note 5 also says to use the nameplate rating for single wall-mounted ovens or counter-mounted cooking units. I don't think a range qualifies as a continuous load, therefore the circuit ampacity need only be 100% (not 125%) of the load. If the load is 7.2kW or less, a 30-amp circuit should be OK. 30Ax240V=7.2kW. The same is true today as it was in 1959. Douglas Hansen

Yes. What is the specific concern? Douglas Hansen

Hello Rocon It sounds like you agree that the scope of 2301.2 does limit conventional framing to 2304 and 2308, and you are disputing whether the table in 2304 brings diaphragms (2305) into the equation. In case anyone without a CBC cares to follow the conversation, I will quote the scoping section here: 2301.2 General design requirements. The design of structural elements or systems, constructed partially or wholly of wood or wood-based products, shall be in accordance with one of the following methods: 1. Allowable stress design in accordance with Sections 2304, 2305 and 2306. 2. Load and resistance factor design in accordance with Sections 2304, 2305 and 2307. 3. Conventional light-frame construction in accordance with Sections 2304 and 2308. Exception: Buildings designed in accordance with the provisions of the AF&PA WFCM shall be deemed to meet the requirements of the provisions of Section 2308. Table 2304.7(3) gives us allowable spans for roof sheathing. It has two span columns. One is for sheathing “with edge supportâ€

The CBC (2006 IBC) does not require roof diaphragms in conventional light frame construction. Diaphragm requirements are found in section 2305. Section 2301.2 gives the available choices of design methods for wood framing, and the sections which apply for conventional light-frame construction are 2304 and 2308, not 2305. The roof in question is not constructed as a diaphragm. Notice the absence of any edge blocking in the second photo. The provisions of the CBC (2006 IBC) for conventional wood framing (2308) allow for lumber or plank sheathing, as well as structural sheathing. Table 2304.7(3) specifically allows wood panel roof sheathing without edge support, such as at a ridge vent or the other joints which are perpendicular to the rafters. ASCE/SEI 7-05 states, in section 12.11.2.2.3, that the sheathing is not part of the design of any required ties or struts, not that it matters since it doesn't apply here. Douglas Hansen

So once again, I'm looking at getting a new digital camera. I've been quite happy with my string of Olympus cameras - current model is the 3040, at 3.3 megapixels, but it's time to get what I'm missing. I'm interested in stuff that shoots in the 5+Megapixal range, is compact, has removable memory (flash card or smart card), and that does a better job on close-ups than my Olympus. Most of all, I'd like something that doesn't take up too much space in my luggage (I'm a road warrior for a living). Any suggestions?