56 votes

How much weight can a large screw safely hold in a ceiling plasterboard?

Is this a bad idea? Only if you want the speakers to stay in the ceiling. Don't forget, you're not simply attaching 8kg to a ceiling made of highly compressed powder sandwiched between two pieces of ...
FreeMan's user avatar
  • 47.2k
16 votes
Accepted

How much weight can a large screw safely hold in a ceiling plasterboard?

Snap toggles. A snap toggle would be perfect in this situation, most are rated for much higher weights than typical drywall anchors. These anchors specifically say they are rated for much higher than ...
matt.'s user avatar
  • 3,051
10 votes
Accepted

Can I wire my infrared heating panels to my existing circuits?

TL;DR Only # 1 is legal. The first 15A circuit should be OK. The number to use is actually 12A/1,440W (often referred to as 1500W based on 125V). That's because lighting and these panels are ...
manassehkatz-Moving 2 Codidact's user avatar
9 votes

How much weight can a large screw safely hold in a ceiling plasterboard?

Depends on the quality and thickness of the plasterboard, if you hit a weak spot... I suggest you find the studs that the plasterboard is fixed too and consider adding braces between the studs for a ...
Solar Mike's user avatar
  • 27.4k
6 votes

Is my plan for running cable 250ft to a subpanel OK?

250 feet is too far to be entirely within a structure or otherwise above ground. SER can't go underground. If you're undergrounding any of this, you'll need a buryable wire type such as MH feeder (...
Harper - Reinstate Monica's user avatar
5 votes

How much weight can a large screw safely hold in a ceiling plasterboard?

I would like to know what a reasonable load is Approximately 0 kg. These anchors are not designed for use in ceilings. Full stop. The closest I got to using anchors in drywall ceiling was when I used ...
Kuba hasn't forgotten Monica's user avatar
4 votes

240v outlet leg b voltage drop under load

Wow, so many things wrong with this setup. The crux is that you are confused about the role of the 3rd pin on a 3-prong dryer. The third pin is NOT ground. It is neutral. You don't have a ground on ...
Harper - Reinstate Monica's user avatar
4 votes

Is there a practical limit to the weight I can put on top of my kitchen cabinets?

The best you can probably do is a proof test. It's just not possible to decide the controlling limit state without significant disassembly. What's the anchor embedment in the concrete, for instance? ...
popham's user avatar
  • 10.4k
4 votes

GFCI Installed right, but no power when load is plugged in

So, it works with the line (including if you plug something into it, presumably, though you're not entirely explicit about that case.) It does not work with the load wires connected, and trips/won't ...
Ecnerwal's user avatar
  • 212k
3 votes

Does my electrical service have capacity for an 80A EV charging circuit?

No discussion of EV charging is complete without viewing Technology Connections' very reasonable advice on circuit size. Update: Power Limiting EVSE's make it possible Since this was initially posted,...
Harper - Reinstate Monica's user avatar
3 votes

How do you estimate the load capacity of a roof truss?

There's so much complexity in trusses that engineers want nothing to do with the analysis. That's why specialized manufacturers exist. Vulcraft comes to mind as the steel analogue to wooden truss ...
popham's user avatar
  • 10.4k
3 votes

How long do you overcut replacement studs on a load bearing wall?

You want them barely snug, but it depends on whether there's any give in the plates. 1/8" is too much if the plates are rigidly supported, and the stud will bow or you'll do damage to the plates ...
isherwood's user avatar
  • 136k
3 votes

Determining ampacity for 3 phase panel with single phase loads

Since the loads are symmetrical, just use VA. So one load is a 100A / 208V breaker, or 20,800 VA. All 3 loads are 62,400 VA. Now what would happen if loads of the exact same VA were 120V single-phase ...
Harper - Reinstate Monica's user avatar
3 votes
Accepted

Determining ampacity for 3 phase panel with single phase loads

For a delta connected load which you have described. The incoming line current will be √3*phase current which for 100 amps would be 173.2 amps. It comes down to trigonometry. The line current is a ...
JD74's user avatar
  • 1,824
3 votes

plywood load-bearing capacity: a stack of several thin ones compared to one thick one

21mm (~13/16") plywood will carry a person up to say 200 lbs. reliably in a sheet that size (about 40x60 inches for the Yanks), assuming proper edge support. The question is one of flex. You ...
isherwood's user avatar
  • 136k
3 votes

Is my plan for running cable 250ft to a subpanel OK?

Because of the typical pricing of 2-2-2-4 being low, due to volume, and the length of run, and the non-competetitive price of other wire/cable options with adequate capacity for such a long run, that'...
Ecnerwal's user avatar
  • 212k
3 votes

Partial Wall Load Bearing?

If there's no support (beam or column) holding it up from below, and nothing coming down onto it from above, it's not load-bearing.
Ecnerwal's user avatar
  • 212k
2 votes
Accepted

Triple 2 x 8 fir beam with span of 12 feet. Will beam support hoist load of 1250 lbs

https://www.engineeringtoolbox.com/wood-header-weight-supported-d_1898.html Extrapolated for (3)2x8 at 12' span, looks like it should be good. You might end up with more deflection (bending of the ...
Fresh Codemonger's user avatar
2 votes

Can a roof be supported with a 2x12 which is cantaleverd 8'?

The International Residential Code (IRC) that governs most residential construction in the US provides for short cantilevers in some situations. 8'-0" cantilevered from a 16'-0" is way out ...
popham's user avatar
  • 10.4k
2 votes
Accepted

How do I calculate the weight tolerance for a steel gate post?

For computing the foundation's strength you need material parameters for your "sand." By "sand," I infer poorly graded sand--that's usually what normal people describe as "...
popham's user avatar
  • 10.4k
2 votes

NEC 220.82c Panel Load Calcs and Multi-zone HVAC

You're adding in parallel-series when you should be adding in series-parallel lol. Put it this way, do you often run the heat upstairs while running the A/C downstairs? I would think not. So you ...
Harper - Reinstate Monica's user avatar
2 votes

Can this wall support books on track shelving?

It depends on the style of support. A triangular bracket (e.g., these) distributes weight from the outside end of the shelf to the wall, and the longer the hypotenuse, the better the distribution. (If ...
DrMoishe Pippik's user avatar
2 votes

plywood load-bearing capacity: a stack of several thin ones compared to one thick one

Your concerns with the thickness of the plywood are misdirected. A 21mm thick piece of plywood would be able to carry the weight of as many adults that could fit on a 1m x 1.6m slab. Therefore it will ...
RMDman's user avatar
  • 28k
2 votes

What can hold more weight, a wall stud or a ceiling joist?

Assuming wood framed walls... The walls wind up supporting the weight either way. Hanging from the joists may distribute the weight a bit more widely since they rest on the plate which is supported by ...
keshlam's user avatar
  • 28.9k
1 vote

How do you calculate a home load for a whole house generator?

For a manually switched generator, you can size based on critical loads: Refrigerator/freezer Basic lighting (doesn't take much with LEDs) Internet equipment Sump pump HVAC - depending on environment ...
manassehkatz-Moving 2 Codidact's user avatar
1 vote

Can I remove double top plate?

Your question is a bit confusing. You've removed nearly the entirety of several walls, so why ask about the remaining boards now? At this point, here's my advice: Read Are there ways to determine if ...
isherwood's user avatar
  • 136k
1 vote

Possible to install a beam in place of load bearing wall?

We're speaking generally here as I can't see the details of the framing. However, I see no real concerns with your plan, assuming... The interior post is directly bearing on the primary beam in the ...
isherwood's user avatar
  • 136k
1 vote

How much weight can a large screw safely hold in a ceiling plasterboard?

It's not often I have a visual representation, but here it is This was our repo house that had a bargain basement contractor brought in to slap some lipstick on and keep moving. So you replace the ...
Machavity's user avatar
  • 24.7k
1 vote

What can hold more weight, a wall stud or a ceiling joist?

I don't like hanging things from trusses, especially when you can't see the panel points where the bottom chord is stiffened by web members. The top chords are probably sized to support 10 psf dead ...
popham's user avatar
  • 10.4k
1 vote

Can I use a 120v load tester to test a 240v circuit by testing each hot wire separately using the ground wire as the neutral?

I see two glaring problems here: You say ground wire is thin. How thin? If it is visibly smaller than the "load" wire, you risk overheating/burning the ground. The heating elements are most ...
Thomas's user avatar
  • 535

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