Hot answers tagged

67

Absolutely not safe. Those trusses were engineered with a heavy (critical) dependency on the bottom chords, which are in tension. Removal has left them extremely vulnerable to collapse due to spreading, especially under snow loads, but also under just the load of the roof itself. The roof system is basically a hinge now. To get a good mental image, ...


64

Fire extinguishers (here in the US anyway) are REQUIRED to not be usable after being discharged, partial or not, because you can never know HOW MUCH extinguishing material was discharged by just looking at the pressure gauge. So the valves are designed with breakaway seals that, once broken, will not hold the charge for very long, forcing you to replace it ...


33

If it's a dry chemical extinguisher (seems likely, most common, particularly with a pressure gauge) the simple answer is that the valve has got dry chemical dust in it and no longer seals properly as a result. When refilling the valve or valve parts will either be cleaned or replaced as needed, the dry chemicals will be placed in the container, the valve ...


31

With no bracing above, you might want to check the out side walls - they are probably already spreading. Once they start moving the stabilization and repair can cost many thousands if the roof stays in place, tens of thousands if it comes down. There are ways to mitigate the damage done, but it needs to be done now before the walls spread, the rafters ...


25

Like Captain Kirk said when he sensed a trap, "It's never a bad time for a battle-stations drill". It's never a bad time to go through and thoroughly inspect your Grounding Electrode System to assure it's in good order. You may have gotten blindsided by something like the water company severing your water pipe ground by inserting a plastic smart meter.


25

I do a lot of work on older homes and see stuff like this all the time. Keep in mind that the equipment grounding conductor (EGC), that bare safety ground, was not always present in wiring systems. If you see old homes - a little older than this one - with two-prong receptacles, those were wired back before the EGC was part of the system. I think when ...


21

While not strictly speaking "single use", I would consider a typical consumer-grade residential fire extinguisher (I have 2 - one on each floor, with the upstairs one near the kitchen) to be a single-use item. This is for a few reasons: Even a moderately sized fire could make good use of the entire extinguisher, so if it is "half used" it is already in the ...


21

It doesn't need to be a GFCI outlet. It needs to be GFCI protected. GFCI protection is conferred by having any particular outlet obtain power power from the LOAD side of a GFCI device somewhere. On most string-topology circuits, a single well-placed GFCI device will protect the whole circuit. If you stick a GFCI tester in there, push the button and the ...


19

You should trim the extra copper off it will not help to have it hanging out there. You also need to make sure when you put things back together the clamp is on the covering for the cable not the individual wires but other than those items I would say it looks safe. A proper torque would be needed to be 100%.


18

The triangle is an extremely stable form of architecture precisely because it has three sides. You remove one side, and you have one of the least stable forms of architecture on account that two members connected at a point can be affected by torque, which is by definition a force multiplier. If you want to play around with it to get a sense, try gluing two ...


15

Some metal products may contain elements or chemicals known to the State of California to cause cancer, birth defects or reproductive harm. Like nickel, molybdenum, lead, chrome, etc. I would imagine that the file manufacturer labels the product out of an abundance of caution so they never have to worry about being sued or prosecuted, even if the materials ...


15

Leaning the ladder against the gutter If the gutters are safe to lean on, and if there are no potential problems with denting them, then that is the way to do it. The ladder will be stable and you will be in a better position for cleaning the gutters than if you were on a ladder leaning on the walls. Some gutters are actually strong enough that you can ...


13

The UPS battery won't be backfeeding into the house service. DC current won't be flowing back through the rectifier diode. I'd be more concerned about doing something wrong with your switch replacements, turning on the power and frying your UPS board. We see this happening all the time here. Play it save and unplug the UPS and anything else on the circuit ...


12

As pictured - very bad idea. It may work IF the roof is re-engineered to carry a lot more of the stress across the top and bottom of the cutout. That means a much beefier horizontal beam on all four sides of his hole AND a rework of the roof by re-trussing the entire structure. Some examples: This one is a Scissor Truss, and also wears the more ...


11

While this should be acceptable, I have personally found a UPS which backfed 240AV out its input pins. I only found this out when brushing against the exposed pins on the wall plug - That UPS went straight in the junk pile! In short, when dealing with mains power, make no assumptions. Use a non-contact voltage indicator or a plug-in lamp or even a ...


10

TL;DR If using the product can release the chemical then slap a sticker on it. I think it's just an overzealous interpretation of: Proposition 65 requires businesses to provide warnings to Californians about significant exposures to chemicals that cause cancer, birth defects or other reproductive harm. These chemicals can be in the products that ...


9

We're reading tea leaves here to guess at NFPA's intent. NFPA writes the "model electrical code" which they offer for anyone in the world to adopt as their law. But politically, NFPA has been having a big problem. Normally NEC changes are fairly trivial in cost: Pull a neutral wire on switch loops, gosh, you're using the /3 Romex instead of the /2. It'...


8

NEC doesn't require AFCI because it does require GFCI, and they are not the same. GFCI outlets protect against electrical shock and this is very important around water. AFCI protects against electrical arcs that come from damaged cords and bad connections. Arcing is super hot, and is responsible for electrical fires. A combination protection device could ...


8

Yes - examples are out there. For practical reasons the chimney tends to be metal, or in older buildings, just a smokehole in the roof.


8

Generally, it's safe to be in an attic with fiberglass insulation without a mask. Is it a good idea? No. It can get into your lungs and cause the coughing you're experiencing and can also irritate your throat. the coughing you're experiencing is probably a combination of the fiberglass and the dust that settles from the venting of the attic. Do yourself a ...


7

What's that cliche "Err on the side of caution" especially if it could be a shock hazard. From what you are describing, you could be building a static charge on your person by sliding across a carpet and discharging to a grounded object. So the static flow is from you (ungrounded) to the panel(grounded). The way you can find out is to shuffle you feet and ...


7

Because of the things you'll be filing with it The same reason sandpaper and other paint-prep supplies contain warnings of lead. The sandpaper doesn't contain lead; but good chance what you're sanding does. To be more specific, you're referring to the text of a Prop 65 warning, presumably text out of 27 CCR 25603(a) affixed to the product package per 25602(...


7

Metals Depending on the alloy, tool steel probably contains cobalt and/or nickel. These are listed on Prop 65. Cobalt: Cobalt metal powder Cobalt oxide Nickel: Nickel (Metallic) Nickel compounds (due to the ambiguity in this line, anything with nickel) Nickel oxide Additionally, there are other metal compounds of chromium, vanadium and even iron that ...


7

Correct. GFCI is actually the ideal solution for the people problem (shocking people) and serves that purpose better than grounding. Assuming no boneheaded bootlegging of grounds. But GFCI (alone) does nothing for the ESD/lightning problem which can damage sensitive electronics or cause goofy problems with radio transmitters. Current travels in loops....


7

The ladder should be placed against the gutter and extended (3' or so) above it, so you can do your work without reaching up blindly. Doing the work as you suggest could cause you to have an unstable body position, reaching up and over like that. If you are concerned about damaging the gutter, you could fasten a wide softner of some sort to the ladder. If ...


7

Chances are the ceiling is damp and you'll be fine. However, I have never been a fan of water and electricity at the same time. With the breaker switched off, take the globe, glass off the fixture. Water probably wouldn't be in the junction box but could have dripped between the box and the ceiling. If there is any dampness, dry everything off. Put the ...


7

Don't Replace, ADD Removing the screws is a lot of extra work, for no real benefit. In fact, you might even find that some of the old drywall screws snap when you try to unscrew them, and then you have no practical choice but to add other screws anyway, leaving the partial screws in the studs. Just add proper cabinet screws. Depending on the layout, you ...


6

A metal bucket is much MORE prone to be attacked by acids in general than most plastics, especially those commonly used for buckets. As it's "waste acid" throw in a box or two of baking soda and you'll neutralize it right then and there. Preferably outside due to the release of carbon dioxide. Or use marble/limestone chips or dust.


6

The metal case of the box is bonded to ground so it is a static discharge. If you reach and touch it again you should now be discharged and nothing will happen. We used to love it when mom bought nylon or rayon socks instead of cotton because they built up the best static, we used to charge up and sneak behind and touch the ear lobe. Lots of fun for brothers ...


6

An outlet tester is a great way to determine that an outlet is wired correctly. They are also useful to show that the correct breaker has been tripped before you start working. Take pictures before you disconnect anything so you'll have accurate information in case you have to come back here and ask questions. Follow the directions that will be included with ...


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