In brief
- Conduit set by eye instead of to a checked route can end up with tight bends, crushed sections and too many cables per tube, and the defects stay hidden once concrete or render covers them.
- A supervisor can catch most of it before cover: check bend radii, conduit fill against the project specification, pull a draw rope through each run, and photograph every route before closing up.
- Close the gap with a short pre-pour inspection routine, a sample conduit run built on site first, and written test records kept with the as-built drawings.
Contents
Conduit routing skills gaps in Gabiley can leave damaged concealed wiring inside walls and slabs, and the damage stays invisible until a circuit fails. The mechanism is simple: conduit set by eye instead of by a checked route gets tight bends, crushed sections and too many cables per tube, so the insulation tears during the pull or the conduit collapses under the pour.
What goes wrong when conduit is routed by eye?
A run set without a drawn route takes the shortest line across a slab, which pushes bends tighter than the cable can follow. General good practice sets the minimum bend radius for a conduit run at several times the conduit diameter, and the exact figure belongs in the project specification, so confirm it with the engineer before you accept a bend. When the radius is too tight, the draw wire cuts into the cable sheath, or the cable jams and gets pulled hard enough to stretch the copper.
Three failures follow from the same gap:
- Long runs with no draw box, so the pull needs force that damages insulation.
- Conduit filled beyond the fill limit in the specification, which traps heat and makes later rewiring impossible.
- Ends left open or unsealed during the pour, so mortar and dust block the tube before the cable goes in.
A supervisor can check each of these before the concrete or render goes on. Mark the route on the drawing, walk it with a tape, and pull a draw rope through every tube while the work is open.
How do you check routing and conduit before cover?
Ask for the routing drawing first, then test the physical run against it. A marked-up drawing with the route agreed on paper is a check worth asking for before bending starts. Where that drawing is missing or does not match the run on the slab, treat it as a signal to stop, walk the route with the electrical supervisor and agree the line on paper before more conduit goes down. That is a check on the work, not a verdict on the contractor's method.
On site, check four things on each run:
- Bend radius against the project specification, measured at the tightest bend.
- Number and size of cables against the conduit size, using the fill limit in the specification.
- Draw rope or draw wire left in every tube, with the ends capped.
- Fixing spacing and support, so the conduit does not sag or move during the pour.
Pull test records and insulation resistance readings taken before cover give the owner something to hold. Ask for photographs of each route with a metre mark or grid reference, kept with the drawing. Where a run fails the check, the tube can still be re-routed while it is open. Once the slab is poured, the only options are cutting concrete or pulling a new surface route.
Why do skills gaps survive on site?
A crew can look busy and still leave bad conduit, because the work is hidden within a day of being done. Wiring is often subcontracted, and the electrical subcontractor may send whoever is free rather than someone who has run conduit in slabs before. Where supervision is one person covering several trades, the conduit stage can pass without a pull test.
Close the gap in three steps. First, have the crew build one sample run on site, bend radius, fill and support included, and accept it before the rest starts. Second, put the pre-cover check on the inspection list with a signature, so the pour cannot proceed until it passes. Third, ask the electrician for training or verifiable experience on conduit in slabs, and keep a record of who did which run.
What to do next
Before the next pour or render in Gabiley, book a half-day pre-cover inspection. Walk every conduit run with the routing drawing, measure the tightest bend, count the cables against the fill limit, pull the draw ropes, and photograph each route. Write the results on one sheet and sign it with the electrician. Do this before cover, not after.
Frequently asked questions
How can I tell if concealed conduit is damaged before the walls are closed?
Pull a draw rope through every run, check the tightest bend radius against the project specification, count the cables against the fill limit, and photograph the routes. A jammed rope or a bend that kinks the tube usually means the run needs re-routing while it is still open.
Does a low electrical bid mean the conduit work is worse?
A low bid can mean fewer draw boxes, thin conduit or less supervision time on routing, but it is not proof. Ask for a marked routing drawing, a sample run and pre-cover test records, and compare the bid against the specification, not against the other bids alone.
Local reporting: this article is written for building work in Gabiley and Somaliland. Ground conditions, prices and rules differ between places; confirm the details for your own site.