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Hex head or some head bolts for trunking

Hi


Im currently nearing completion of a steel trunking job and was looking for some advice. The 3x3 steel trunking is fixed on top of unistrut running perpendicular to it at regular intervals. I used M10 zebedees and hex head bolts for this. I now wondered if I should have used dome head bolts instead for the same reason as M6 dome head bolts are used to bolt the trunking together - to protect the cable. Was just wondering what others use in this circumstance


Thanks
  • Former Community Member
    0 Former Community Member
    M10 Hex heads holding trunking down on Unistrut is perhaps a bit of overkill


    More traditionally would be M6 Slotted Dome heads (ie gutter bolts)


    Assuming you don't need a lump hammer to put the lid on, and you take a bit of care when installing cabling, I wouldn't have any reservations about hex heads showing inside the trunking


    Regards


    OMS


  • Thanks OMS


    Thankfully there aren’t many circuits in the trunking however who knows what may be added over time. I think I’ve found some M10 dome head bolts that tighten with an Allen key after a bit of googling so for peace of mind I might replace the hex head bolts with these


    Thanks for your reply


    Peter
  • You could always get some plastic covers for them, blob of superglue must be easier than swapping them
  • is it actually going to vibrate and fret the insulation? - if it is part of some big machine, perhaps, but in a building, I'd not think so.
  • Hi


    thanks all for your replies. On another note, what fixings do others use when fixing trunking for example to a surface? Countersunk or panhead screws? Different contractors I have worked with have used both. I must admit on larger steel trunking, a single red rawlplug and screw every couple of feet doesn’t fill me with much confidence especially if the trunking could be eventually filled with cables, it’s quite a weight. On this job I used frame fixings and a large flat washer. Some call them concrete screws, they screw into a predrilled hole with no plug required, kind of like a thunderbolt. They have a countersunk head with a torx fitting to drive them in. I must say they did a good job. Do others prefer panhead or countersunk screws for this application