drilling in rafters

[bric123]

hi guys.
last year i had loft converted to storage room/study. this involved removing some of the truss rafters and replacing with purlin/struts and new collars at the apex.recently noticed whilst taking down a downlight that the electrician has drilled a small hole in each of truss rafters on one side of the roof near the apex and just above the new collars in order to run his wires. have read over and over that drilling through truss rafters is a no no but with the new collars in place could this still be a problem.
looking for advice as building knowledge limited. thanks.

 

[big-all]

what size are the timbers w h d!!
is the hole greater than say 10%!!

truss rafters tend to be in the region off 3.5x1.5" ish iff your new timbers are chunkier than the surrounding timbers there is probably a built in safety margin
also normal drilling permits 25% holes away from the ends so an overside timber with a less than 10% hole may be fully ok!!!

 

[bric123]

the holes he drilled are approx 1/2inch in the truss rafter just above the new collar which is nailed on to it. one hole in each rafter the length of the room to run his cables. his choices were limited since there isnt a space at the apex between the truss rafters and the new collars so he had to drill through one or the other.since the truss rafters are no longer the main supports shouldnt this be ok?

 

[big-all]

are they cut before they meet another member off the roof trussing!!!

 

[bric123]

not sure what u mean. the truss rafters have been cut further down and replaced with purlin/struts. at the apex they are still joined with steel joining plate plate .the holes he drilled are a few inches away from this .and new collars attached just below.

 

[big-all]

truss rafters are thinner and there strength is in tension[pulling]
if they have been cut there structural strength has been fully compromised and there role will be reduced to light span support or compression

if you remove tension then the support must be increased drasticly
all i am trying to work out is iff the remaining timber will be compromised by a a hole

have you got a picture off the origional structure and the new supports

 

[bric123]

no, but will try and take a couple of the new supports if it helps although they are pretty well concealed now with new plasterboard walls, insulation etc.would there be warning signs if they were compromised i.e. cracks in rafters around holes etc. there is none of this or would it be something i should check periodically?

 

[big-all]

if the room is fully loaded and you have had high winds and heavy snow since then i wouldnt worry to much unless you hear creaking and groaning in that area
and signs off cracking

 

[bric123]

ok, thanks. room was done about 10 months ago and we have had all sorts of weather including the recent heavy snow. also had 2 guys on the roof re-pointing ridge so should be ok. appreciate the replies mate. the internets great but you can get so much information it can scare you witless.nothing like talking to a man who knows.
cheers.