A New Way to Wire Metal Stud Buildings
While constructing a metal stud, brick and concrete 30,000-square-foot 
manufacturing building for his own use, John Grady, a PE and also a licensed Master electrician for 45 years, decided to get involved in the construction work personally.
He had a long career in medical x-ray equipment, and the power engineering required for those systems, and decided that two or three years doing some “real construction” would be a welcome change from the front office.
The project included many other interesting aspects, too long to get into in detail in this article, including rehabbing a 300 kw hydropower facility.
While doing the work required, he was surprised to see that even after many years away from the trade, the methods used had not evolved at all. 4X4 boxes still needed plaster rings, the wires from the receptacle still refused to fold because the AC/MC clamps are right under the outlet, the box was still too shallow, the physical attachment to metal studs still required a “do it yourself” kit, and there was still not enough volume in the boxes to do things the right way. And the drywall guys will still cut the wires, and the 2 gang three-way switch boxes were still too full to wire in a workmanship-like manner.
The right way means use of a 3 or 4 wire multi circuit feed, to cut home runs by 3X, but no way could you do that without adding additional blank cover junction boxes, etc.— barely worth it! So, like most electricians he ended up with 3 times as many AC cable runs to the panel as might otherwise have been possible with multiwire.
After personally installing about 50 of these, he decided to design a new system. The result is the Grady Box ä. Not just a box, a system to do metal stud wiring right.
The problem to be solved was geared to a typical office in a metal stud building, or a hotel room—whatever! What is often needed per room group is two three way or two single pole switch setups, and for properly spec’d buildings, probably more 2-gang or four position receptacles than ever before — and two or three feeder circuits.
While plaster rings, etc., can be used with the Grady Box ä, the initial focus became 2-gang devices—a difficult job with present 4-inch square boxes and 2 gang rings. In fact deep inside, most electricians immediately think, “Oh no, not another one of these!” when they see 2 gangs and 4 MC cables.
John Grady describes what was wrong and how it was fixed:
(1) Mount to open or closed side of metal stud
- The holes electricians used to drill in the box sidewall are already there, and a hole for a screw driver opposite them.
- No fabricating metal stud scraps to mount the box on the open side – a bracket for the open side instead!
- Router goes around outside front of box, so no front mount straps are allowed—and no cut wiring is the result.
- No bump in finished dry wall caused by bracket mounts either.
(2) Box volume for multiwire feed and 2-3 ways, by design
- Clamps are moved out of box, no wires cut on the clamp edges;
- Clamp screw studs come forward, no screws to cut off the back of the box when against block walls;
- Much deeper box because back screws are gone (48 cu. in.);
- Conduit and MC/AC enter all on one surface (top);
- Wires fold neatly because they all come from the top, 15 #12 – OK;
- Pass & Seymour Plugtail ä fits easily—more labor $$ saved;
- 2 duplex, no hassle;
- Multiwire splices—no hassle; and
- No series feeds needed on outlets to save space.
(3) Router kept out of box interior by design
- You know why.
- Replacing one damaged box requiring re-terminating AC cables after finish can cost $500.
(4) 1 gang, 2 gang or 4 inch raised covers, same deep box
- No loose parts, rings, metal stud mounts, 2 gang versus 4” square inventory, BX connectors, etc.
- One box does it.
But why does this allow a new way? Unlike what we all do now (a loop system) there is no problem putting 4 #12/2 MC (or 3 #12/4) into the box. This allows a “tap” layout. So, single runs to an outlet by itself not only save time, it saves wire and physical work. Better multiwire cable (superneutral) can be used as a 3-circuit homerun; the panel comes out neat and clean, 2-3 circuits per homerun, fewer KO, fewer BX clamps…much less labor!
A further dollar savings can be found in making up all the splices during rough-in; this allows you to turn it on (which you cannot do with loop receptacle wiring) so it is tested and even used for trade power and temporary lighting before the dry wall goes on. The finish electrical work becomes apprentice work…just add the finish devices and covers.
It is a simple idea, but one so obvious we can only wonder why it took so long to appear. We believe it saves at least 10 minutes an outlet, and at current labor rates it is the only way to go. If you add in the cost of exchanging even one switchbox scrambled and cut by a careless drywall router (which you find out about long after your drywall pal is gone) the electrical contractor comes out way ahead. Then you add the cable run labor savings…
We think it is a new way, made possible by a new patented box.
Finally, the best part of all…the job is of uniformly higher quality at a better total cost. The result—work electricians can be really proud, which ultimately is the name of the game.
