Cutting 5mm squared/circular hole into wardrobe backboard

[pcdj]

Didn't consider this to be strictly woodwork; can a moderator please move this to a different category if 'general' is inappropriate?

I need to cut through some backboard in the back of my wardrobes to feed some power cables through. I can't remove the backboard, and unfortunately don't have access to the rear of the wardrobe via the sides - only via the top - which means access to where I'll need to make the holes is only achievable via the front.

I've attempted this before using a drill bit, taking it slow, and putting masking/sellotape over the area being drilled, but every time it's not given a nice clean cut and it starts tearing the backboard up.

I guess ideally what I'm looking for is something akin to a 5mm hole saw, but they don't seem to exist.

Does anyone have any other suggestions for tooling which I may have overlooked for the job?

 

[stealthwolf]

Can you get some solid timber behind the backboard? Probably achievable if you can slip it in from the top.

Otherwise what about making a larger hole and then using a rubber grommet to line the hole and hide the tearout?

 

[foxhole]

5mm hss drill bit, simples.[5mm small for all but tiny cable?]

 

[lostinthelight]

“Power cables” and “5mm hole doesnt make sense to me , are the cables that small or is this a typo?

 

[pcdj]

Not a typo. 12V power. Thanks.

 

[lostinthelight]

Not a typo. 12V power. Thanks.

Whats the backboard material and are you tearing it up with, have you tried a brad point twisted wood drill?