What a mathematical error!!!!

[HappyHippyDad]

I cannot believe I did this. I am almost obsessive with mathematical calculations. In fact, I actually try to be less obsessive as it takes so much time and mental exhaustion to be exactly correct to the mm/cm/m.

I had to measure a long run to a new sub DB that I was putting in. It was an awkward run, twisty and turny in a barn, up and down, and into a field.

It took a lot of will power but I decided for the first time ever to just 'pace it out', rather measure it. I felt really uncomfortable as the OCD was kicking in, (but also a tiny bit brazen which felt good ) but I did it. An 80m (paced out) length. I then added on 10% and purchased 88m of cable.

Went to the job yesterday, spent 2 hours getting the 88m of heavy SWA in to the twisty turny, high up places........

I was short.....

by 37m!!!!!??

That's ridiculous, I have never been short in my life. Literally never. I always have excess. Too much excess, I have sooo many off cuts of SWA ready for scrapping.

37m!!??

Half a day spent getting the extra cable, running it and joining it.

I will never pace a job again. I shall revert back to my mathematical OCD and revel in it, rather than fight against it

What on earth went wrong!!!???

 

[DPG]

I cannot believe I did this. I am almost obsessive with mathematical calculations. In fact, I actually try to be less obsessive as it takes so much time to be exactly correct to the mm/cm/m

I had to measure a long run to a new sub DB that I was putting in. It was an awkward run, twisty and turny in a barn, up and down, and into a field.

It took a lot of will power but I decided for the first time ever to just 'pace it out', rather measure it. I felt really uncomfortable as the OCD was kicking in, (but also a tiny bit brazen which felt good ) but I did it. An 80m (paced out) length. I then added on 10% and purchased 88m of cable.

Went to the job yesterday, spent 2 hours getting the 88m of heavy SWA in to the twisty turny, high up places........

I was short.....

by 37m!!!!!??

That's ridiculous, I have never been short in my life. Literally never. I always have excess. Too much excess.

37m!!??

Half a day spent getting the extra cable, running it and joining it.

I will never pace a job again. I shall revert back to my mathematical OCD and revel in it, rather than fight against it

What on earth went wrong!!!???

Did you have a tight skirt on? So you couldn't get as much of a stride.

 

[HappyHippyDad]

Did you have a tight skirt on? So you couldn't get as much of a stride.

That's just at the weekends, never during the week.

 

[HappyHippyDad]

Did you have a tight skirt on? So you couldn't get as much of a stride.

Plus, it would have had to have been the opposite wouldn't it. Almost doing the splits on each stride!

 

[DPG]

Plus, it would have had to have been the opposite wouldn't it. Almost doing the splits on each stride!

Good point. That’s another mathematical error then!!

 

[nicebutdim]

Measure six times, cut once.

 

[SparkySy]

When I started I used to do that pace it out, sometimes 2-3 times just to make sure, I always ended up with way too much cable, and sometimes oversize due to calculating the Volt drop on the cable that was too long!
I bought a trundle wheel a 50m tape measure and a 30m laser measure, use them daily and the few sets of them I have had over the years have saved me loads of stress and probably more than paid for them!

 

[ipf]

I usually pace it out.......but, if it's new to you, don't run before you can walk.......to coin a phrase.

 

[buzzlightyear]

That's ridiculous, I have never been short in my life.

why what size when you set off, is it measure once cut twice .

 

[littlespark]

Measured in metres, ordered it by the foot?

I can’t see where you could go wrong…. Unless you’ve forgotten how to count in your head.

 

[Resu]

Measure six times, cut once.

More like measure once, join six times!

Usually if we're pacing a couple of us would do it and take an average. Been a bit off a few times but usually the other way. 37m is alot!

Now I think of it the last run of SWA I pulled in ended up about 6m short on a short run of about 50m. The digger driver who laid the ducting was still on site at the time and offered to measure it out as he had a proper measuring wheel. I took the number he gave me and did the usual rounding up but still ended up 6m short!

Might be a chance the wholesaler has made a blunder?

 

[nicebutdim]

One of my colleagues paces everything and never goes wrong. I know what would happen if I paced distances, so

More like measure once, join six times!

Usually if we're pacing a couple of us would do it and take an average. Been a bit off a few times but usually the other way. 37m is alot!

Now I think of it the last run of SWA I pulled in ended up about 6m short on a short run of about 50m. The digger driver who laid the ducting was still on site at the time and offered to measure it out as he had a proper measuring wheel. I took the number he gave me and did the usual rounding up but still ended up 6m short!

Might be a chance the wholesaler has made a blunder?

A colleague paces everything and I'm yet to see him get it wrong. I know how that would work out for me, so everything is measured + a bit. If it's a particularly awkward run I also get someone else to work it out, without first telling them my estimate, and see how the two compare.

 

[brianmoooore]

I've always been near enough spot on when pacing out for a buried cable. I can almost guarantee to be within a metre on a 100m run, but errors can occur if there are vertical bits and runs inside buildings that are measured separately. It's all to easy to forget to add in one of these extra measurements.

 

[Lucien Nunes]

@HappyHippyDad when did you last send your legs off for calibration?

Seriously, the way to do this is to use both measurement methods side by side for a dozen or two jobs, comparing and adjusting your pace and eyeball estimates until they agree consistently with the tape measurements. Once you are satisfied that the results are accurate and repeatable enough you can bypass the tape measure stage.

Before I had minions to do it for me, I used to make audio / video / control cables in the workshop that would often be 5, 10, 20m in length and I would impress people by just pulling the cable off the reel rack and geting the length accurate to a fraction of 1%. E.g. two 10m cables pulled separately would be within a couple of cm. The only reason I could do this was that I had carefully calibrated my reach by repeated comparisons with the tape and would refresh the calibration regularly to avoid long-term drift.

A method that I use when estimating installed cable length is to visualise conduit lengths in position. I can very easily gauge where the end of a 3m would be, even on a run with a couple of bends in. So I will look at the wall and imagine a 3m length in place, rigidly fix the end point and then imagine the next length following on from that. If a 3m won't fit in one 'visualisation' then I imagine a cut length that is always a multiple of 0.5m.

 

[mattg4321]

Not sure how you could be that far out. Pacing it out never lets me down. I usually end up with too much if anything.

As above it could be a wholesaler error? They once gave me 50% too much as their machine played up!

Also could be you forgot to add a section etc? Did you pace it again when you went back?