DIY Electricians, Posidriv is your friend

drnickriviera · Mar 25, 2025

I'm not sure why i'm just leaning about this, but the screws on things like outlets and terminal bars are posidriv. Looks like a phillips with a square drive inside. I've used square drive mostly for electrical work, but have had issues with getting good torque on them. Pz 1 for the screws that hold it to the box and pz 2 for the wire screws. Made my life so much easier replacing 10 outlets yesterday. Didn't cam out even with screws that had paint on them.

What sucks is that some posidriv screws aren't marked. Some will have tick marks at 45deg to the phillips slots. So if you are wondering why your phillips screwdriver doesn't want to work right, make sure it isn't posidriv.

Greenman · Mar 25, 2025

It's odd that electrical went posidriv, while most cabinet, deck and construction screws went to torx. It's annoying that I need 9 different screwdrivers in my tool box.
Edit: It's actually more like a dozen different screwdrivers.

Red Squirrel · Mar 25, 2025

I find typically the green Robertson will work on outlets and such and the red one will work on the screws inside boxes, like the ground screw. Same size as most standard construction/deck screws as well, so when mounting a box can use the same driver/bit.

I have seen the odd time where the yellow one will work on some stuff too. I'm not sure if these colours are actually standard but of all screwdriver sets I have they seem to be.

drnickriviera · Mar 25, 2025

I've had good results with robertson, but posi is another step up. If you look at the head design, you see that you don't get contact on all 4 sides of a robertson.

Question is, when did they change and why didn't they tell us peasants? I've bought klein electrical screwdrivers and even a wiha electrical screwdriver kit, but neither has posidriv, you have to buy them all separate. I'd have to double check, but i'd bet EMT set screws are posidriv too

BoomerD · Mar 25, 2025

I bought a Vessel JIS driver for PC work. Grips much better than a standard Phillips.

Greenman · Mar 26, 2025

Since were here, lets not forget JIS screws that are almost philips.

Paperdoc · Mar 26, 2025

I'm Canadian and a big fan of Robertson screw design (invented in Canada), They are used widely here, less so elsewhere. I find them much better than Phillips for good torque without stripping the socket, and very good for keeping the screw on the bit tip when reaching in to install.

I read that the newer Posdriv design is even better for torque without stripping, not sure I need that. On electrical equipment I am used to a combo design with Robertson socket plus a straight slot cut across the diagonal of the square. I use the Robertson feature for most things. On a recent install of panels and wiring for a 120 / 240 VAC 100 A service in my garage I got a proper torque wrench and Robertson tips to tighten all connectors according to specs on the panel and breakers. Even on the largest (screws for the 000 gauge feeder cable) there was no problem, although those do not require the very high torque of some rusty car parts. On rare occasions if I find I need more torque on a larger Robertson screw I will get a very wide straight slot driver blade (wider than the screw head) and use the slot feature for a final extra twist.

With drivers for straight slot, Phillips, Robertson and Torx among my tools, not sure I need a fifth. Already I refuse to buy the special "Security" version of Torx.

herm0016 · Monday at 7:11 PM

posidrive sucks. Robertson is far superior to others.

Greenman · Tuesday at 8:39 AM

herm0016 said:
posidrive sucks. Robertson is far superior to others.

Robertson was a good choice before Torx became common. Now that the best wood screws are Torx there isn't any reason to use anything else.

DIY Electricians, Posidriv is your friend

drnickriviera

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drnickriviera

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herm0016

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