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Electrical

Joists - notched in the middle of their span

Anonymous user 01/03/2024 - 2.53 PM

Hi guys, just had an electrician install new sockets - but he has notched the joists, all along a room - and in the very centre of their span. I think that is not to specs - there are regs on where you can notch and the centre of the beam's span seems the worst spot possible. The notch is appprox 1.5 cm so is below 1/8th of the joist height. But still. I am concerned that these same joists were already notched for central heating and are quite bouncy. Your opinion? --- turns out the notches were quite old, the electrician reused them rather than make further holes ---

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1 Answer

kevin cassidy building contractors

Rating: 5 out of 5
Accrington
If notched into the joist cables are required to be provided with mechanical protection sufficient to prevent penetration of the cable by nails, screws and the like (NOTE: the requirement to prevent penetration is difficult to meet) Maximum depth of notch should be 0.125x joist depth. In a zone between 0.07 and 0.25 of joist span. Normal practice is to drill holes max 0.25 x joist depth at least 50mm from top and bottom. In a zone between 0.25 and 0.4 of joist span.
Answered1 December 2019
2