624 reputation
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bio website ericlippert.com
location Seattle, WA
age 42
visits member for 3 years, 5 months
seen 2 days ago

Eric Lippert develops C# analyzers at Coverity. During his sixteen years at Microsoft he was a developer of the Visual Basic, VBScript, JScript and C# compilers and a member of the C# language design committee; he is now a C# MVP. He is on Twitter at "@ericlippert" and writes a blog about programming language design and other fabulous adventures in coding at http://ericlippert.com.


Mar
13
comment Attach net/hammock to interior walls
The true tension force you need to overcome is therefore somewhere between 400 pounds at a minimum, and infinity at a maximum, depending on the angle at which you want the hammock to make when loaded. What is that angle? a 400 pound load with an angle of five degrees supplies the equivalent of 5000 pounds of force to the wall, so it matters a lot. Do a web search for "sling angle factor" for charts showing the amount of extra force supplied as a factor of angle.
Mar
13
comment Attach net/hammock to interior walls
Something to keep in mind is that the angle at which the hammock lies when under load dramatically changes the tension force which is applied by the hammock to the walls. Imagine for example you wanted no deflection whatsoever from a horizontal line when the hammock is loaded. Obviously the hammock would have to be infinitely tensioned for that to happen. Now imagine you suspended the hammock from the ceiling straight down, so the angle was purely vertical; clearly the tension with a 400 pound weight is 400 pounds of tension.
Mar
13
comment Is Duck/Duct tape safe to use to insulate mains wires?
Can you more clearly describe the circumstances under which you have non insulated mains wires?
Mar
13
comment water backing up into both sinks, whether running the disposal or dishwasher
You've described a scenario, but you forgot to ask a question. What's your question? "I need help" isn't a question; what specifically do you want to know?
Dec
22
awarded  Peer Pressure
Oct
27
awarded  Yearling
Oct
22
comment Is there a way to change this circuit so that the receptacles are not controlled by switches?
@MarkTraina: That I don't know. I've never seen that behaviour in a multimeter.
Oct
22
comment How do I fix a broken brass drawer pull?
Then I'd go for brazing on new metal as the answer suggests.
Oct
22
comment How do I stop a dimmer switch from humming?
What brand is the dimmer you bought?
Oct
22
suggested rejected edit on Can I branch off of a 2 pole 30 amp 10-3 wire found abandoned in a junction box?
Oct
22
comment Is there a way to change this circuit so that the receptacles are not controlled by switches?
@MarkTraina: Also, as I always counsel people who are getting into homeowner wiring: if you do not have a solid grasp on what the relationships are between volts, amps and watts, if you can't off the top of your head immediately say that a 60W bulb will draw 0.5A on a 120V circuit, then learn that before you go on. You wouldn't want a contractor to work on your house who was not clear on the difference between pounds, inches and minutes, so don't be a guy working on electrics who confuses current, potential and power.
Oct
21
comment Is there a way to change this circuit so that the receptacles are not controlled by switches?
@MarkTraina: More generally, you want the neutrals to have the property that any neutral wire on a given circuit is an uninterrupted path back to the neutral bus on the panel. Similarly for safety grounds; you want there to be one grounding system in the house that all the safety grounds tie into. When I bought my house there were two, and therefore it would be rare but possible to have a voltage difference between them.
Oct
21
comment Is there a way to change this circuit so that the receptacles are not controlled by switches?
@MarkTraina: Imagine a light fixture hooked up directly to the breaker. The light is on all the time. Now you decide to introduce a switch to control the light. You can put the switch on the hot wire or the neutral wire; either will cause the light to go off when the circuit becomes open. But if you switch the neutral then the hot is unswitched and is always providing voltage to the light fixture. That is far more dangerous than the alternative, so code is to always interrupt the hot when you add a switch.
Oct
21
comment Is there a way to change this circuit so that the receptacles are not controlled by switches?
@MarkTraina: An "open" wire is a wire that is not at present connected to anything, so an open ground is what looks like a ground wire, but in fact is not connected to a copper rod driven into the earth anywhere. An open ground is dangerous because it looks like a safety system but in fact is no such thing. An open wire is called that because normally you make a wire open by opening a switch. Internally the switch has a mechanism that physically moves two wire ends together or apart; if there is a gap, no current flows. If the gap is closed, current flows.
Oct
21
comment Is there a way to change this circuit so that the receptacles are not controlled by switches?
@MarkTraina: Not realizing that the ground was open, I tried testing a white wire against the ground, got no voltage, and concluded the white was neutral. It was hot. It was on. I could have shocked myself or others. I should have tested against a known ground rather than assuming incorrectly that the ground was the only correctly wired thing in the box. I have a healthy respect for just how terrible homeowner wiring can be; again, proceed with caution as you learn how to do this.
Oct
21
comment Is there a way to change this circuit so that the receptacles are not controlled by switches?
@MarkTraina: Case in point, I recently rewired a friend's bathroom light where the previous owner had a box in which black, white and red wires were all used for hot and neutral; at one point there were red, black and white wires taped together. Everything was held together with tape, the grounds were open, and the switch interrupted the neutral. If there was a way to do it wrong, they did it wrong.
Oct
21
comment Is there a way to change this circuit so that the receptacles are not controlled by switches?
@MarkTraina: That's right. The safety ground of course is never interrupted in a correctly wired box, but again, you don't know whether the wiring you are investigating is correct. That's the point of the investigation. So proceed carefully deducing new facts starting from known facts, like "this is a good ground, this is a good hot".
Oct
21
comment Is there a way to change this circuit so that the receptacles are not controlled by switches?
@MarkTraina: There are lots of videos on the internet on how to use a voltmeter; if you're going to be diagnosing electric circuits then knowing how to use this tool correctly is going to be important, so I would start there.
Oct
21
comment Is there a way to change this circuit so that the receptacles are not controlled by switches?
@MarkTraina: A voltmeter will only tell you that there is a voltage when it is part of a circuit. If you touch a voltmeter probe to a hot wire but do not touch the other probe to anything, that tells you nothing because there is no circuit. If you touch it to a piece of metal that is not grounded, that's not different; the probe is already a piece of metal that is not grounded. To test whether something is hot, you need a known ground. And conversely, to test whether something is grounded, you need a known hot.
Oct
21
comment How do I wire a ceiling fan?
Nothing says "dangerous amateur" louder than finding wires wrapped in electrical tape. Use wire nuts.