Question: In a recent "Problem Clinic" column (Concrete Construction, January 1971, page 27) you ask a seemingly simple question regarding wiring in concrete. There are many ramifications.
Answer: In our work we are concerned more with cost of labor and with simplicity of installation. We divide the plumbing and the wiring. We cast all duct into the concrete walls so that all that is necessary later is to pull wires through.In each concrete wall panel (48 inches wide by 96 inches high) we include 3/4-inch thinwall with outlet box or boxes. Material cost varies from $1 to $2 per panel.When we pour our panels we add along the top a 1 by 1 1/4 by 48 inch block of wood (removed later) to form the raceway. Romex can then be laid in along the top in this raceway and wired into vertical conduits. If codes require metal enclosures, BX can be substituted or UL approved metal conduit this size with the covers can be cast into the panel instead of the block of wood. Then standard 600V TW No. 12 or No. 14 wires can be employed, saving time and money.This way all conduits will always be high and dry and wiring can be easily installed and just as easily changed later. This is just good wiring practice.
Paul Juhnke, President
Low Cost Housing Institute