B-Line B121ZN Eaton series strut fittings and accessories, 3.93" Height, 5.37" Length, 3.5" Width, 1.52lbs, Steel, Eight hole double corner connection, 90 deg, Thickness 1/4 in, Electro-plated

The B121ZN is an eight hole double corner connection bracket that ties two pieces of strut together at 90 degrees. It is a double corner, so it braces the joint on both sides of the corner rather than on one face only, which is what you want where a strut run turns and has to carry load through the turn. Eight bolt holes total, four per leg.

Electro-plated zinc is a thin indoor coating. The B121ZN is fine for dry interior mechanical rooms, ceilings and conduit racks, but for exterior, parking structures, wash-down or corrosive areas you want a hot dip galvanized or stainless fitting instead. Matching the fitting finish to the strut finish matters too, since mixing plated fittings on galvanized strut outdoors accelerates corrosion at the joint.

No. The B121ZN is supplied as the bracket only. Eight holes means you need to order eight strut nuts and eight bolts (typically 1/2 inch hardware for standard 1-5/8 inch strut) separately to land it, plus washers if your spec calls for them. Budget the hardware into the takeoff so the crew is not short at the corner.

It measures 3.93 inches height, 5.37 inches length and 3.5 inches width, and weighs 1.52 lb. Worth checking the 5.37 inch leg dimension against your clearance if the corner lands near a wall, deck or adjacent trapeze, because a double corner bracket projects on both faces of the joint.

Use a flat angle or single corner gusset where the joint only sees light load and you need one face clear. Go to the double corner, like the B121ZN, where the corner has to be stiff in both planes, such as the knee of a trapeze or a rack leg to header connection. The quarter inch section and eight bolt pattern spread load across more of the strut than a two or four hole plate does.

Same part. B-Line is Eaton's strut and support line, and the manufacturer part number is B121ZN. If a drawing or a takeoff calls out Eaton B121ZN, this is what fills it. The ZN suffix denotes the electro-plated zinc finish.