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Discussion Starter · #1 ·
I have seen some similar questions but still trying to sort out. I am adding 2 junction boxes in my attic, one under the roof peak and one near the edge. From the Canadian Electric Code 12-514 I see that if the distance from top of joist to rafter is more than 1m the NMD90 I am running will need to be protected, for this I am drilling holes in through the joists and stapling along side of joists where necessary.

First question, in 12-3014 it states a junction box will have a vertical space of at least 900mm, is this from junction box to bottom of rafter or is this the distance from top of joist to bottom of rafter?

Next question, I would like to have the junction boxes stick above the blow in insulation so they can easily be found, can I add a vertical 2x4 to mount the j-box on (or use ridge brace) and run wires along joists and up 2x4? Or can I mount to bottom of rafter? If not then should I just leave j-box below insulation and mount to side of ceiling joist?

Thanks

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I have seen some similar questions but still trying to sort out. I am adding 2 junction boxes in my attic, one under the roof peak and one near the edge. From the Canadian Electric Code 12-514 I see that if the distance from top of joist to rafter is more than 1m the NMD90 I am running will need to be protected, for this I am drilling holes in through the joists and stapling along side of joists where necessary.

First question, in 12-3014 it states a junction box will have a vertical space of at least 900mm, is this from junction box to bottom of rafter or is this the distance from top of joist to bottom of rafter?

Next question, I would like to have the junction boxes stick above the blow in insulation so they can easily be found, can I add a vertical 2x4 to mount the j-box on (or use ridge brace) and run wires along joists and up 2x4? Or can I mount to bottom of rafter? If not then should I just leave j-box below insulation and mount to side of ceiling joist?

Thanks

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Those are cavity measurements, 1m or less so your not walking over wires laying over rafters and 900mm so you can access the junction box. My journey man has never instructed to drill out rafters. You can run a board or duck in and out if the 1m area and staple along the rafter.
 

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Discussion Starter · #3 ·
Those are cavity measurements, 1m or less so your not walking over wires laying over rafters and 900mm so you can access the junction box. My journey man has never instructed to drill out rafters. You can run a board or duck in and out if the 1m area and staple along the rafter.
Thanks Phillipd. So for the junction box can I mount to bottom of rafter or tack a 2x4 to the ceiling joists and mount to this so that it's not buried in insulation?
 

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Thanks Phillipd. So for the junction box can I mount to bottom of rafter or tack a 2x4 to the ceiling joists and mount to this so that it's not buried in insulation?
I’ve done it before and never told you can’t so unless one of the licensed guys on here fills in the blanks I don’t see why not
 

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Phillip is spot on. I've never drilled a rafter in my entire career and have no plans to do so before I retire. ;)
 

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Discussion Starter · #7 ·
Turns out my attic is only greater than 900mm right at the roof peak otherwise everywhere else it is less. I am needing to add a junction box onto a line coming off the panel but the location would be less then 900mm, so I assume this is not okay? See photo

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