Metallics JHW12312 Anchors 1/2 x 3-1/2 Hmmr Drv Wdg Zn-C (Jar 25)

It is zinc plated carbon steel, which is a dry interior or protected finish. It will handle a dry mechanical room, slab, or interior wall fine, but exposed exterior concrete, a parking deck, a pool area, or anywhere it gets wet and salted will corrode the plating. For those conditions move to a stainless or hot dip galvanized wedge anchor in the same 1/2 inch diameter.

A wedge anchor like the JHW12312 is a solid-concrete anchor. It works by expanding a clip against the wall of the hole, which needs the uniform compressive strength of poured concrete. In hollow block, brick, or grouted CMU the cell wall can crack or the anchor can spin in a void. Use a sleeve anchor, a screw anchor rated for masonry, or a toggle for hollow block instead.

Work backwards from the 3-1/2 inch overall length. Whatever embedment depth your job requires in the concrete comes off that total first, and the remainder is what is left to pass through the strut channel, bracket, or base plate plus the nut and washer. For thicker standoffs or double-stacked steel at 1/2 inch diameter you want a longer anchor than 3-1/2 inches.

25 anchors per jar, and the jar is the pack unit, so one order quantity is 25 of the 1/2 x 3-1/2 anchors, not a single piece. Figure your count by hole, including the spares you will lose to blown-out holes, before you decide how many jars you need.

No. A wedge anchor is a permanent fastener, the clip sets against the concrete once it is driven and will not retract. You can back the nut off and remove the fixture, but the anchor body stays in the slab. If you need to clear it flush, cut or grind the stud down. For an install you expect to relocate, use a threaded insert or a screw anchor that backs out.

At 1/2 inch diameter it is the size used for the heavier overhead and wall work in an electrical install: trapeze and strut supports for conduit racks, cable tray hangers, transformer and panel mounting feet, motor and equipment bases anchored to slab. Lighter single-conduit straps and small boxes do not need 1/2 inch; a 1/4 or 3/8 anchor covers those.

Order it as Metallics JHW12312. That number covers the 1/2 x 3-1/2 inch zinc plated hammer drive wedge anchor supplied 25 to a jar, and it is the only configuration under that part number, so there is no length or finish option to specify alongside it.