Determining Minimum Trunking Size

[Ollectrical]

Hi there! I have successfully completed all parts of my coursework for level 2 and 3 2365, bar one notorious question:

A trunking run within the electrical switch-room area is to contain the following single-core thermosetting stranded cables

• 35 x 1.5mm2
• 25 x 2.5mm2
• 12 x 4.0mm2
• 10 x 10.0mm2
• 5 x 16.0mm2

Determine the minimum trunking to be used.
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Using appendix E of the OSG, I have calculated

35 x 9.6 = 336
25 x 13.9 = 347.5
12 x 18.1 = 217.2
10 x 36.3 = 363
5 x 50.3 = 251.5
336+347.5+217.2+363+251.5= 1515.2

Using Table E5 of the On-Site Guide, and then Table E to identify the dimensions of the trunking using the factor, It is clear that

Trunking factor 1542 is most appropriate, giving a trunking dimension of

100 x 38
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I have been told this is incorrect, and cannot understand where I have gone wrong. I have multiplied the amount of cables by the value of Table E5 (Stranded), added up the total of each cable value, and flicked over to Table E and used the trunking factor equal to or higher than, which is 100 x 38, due to the trunking size being 1515.2

Is there a Spark in shining armour that might add to my knowledge and point me in the right direction. Many Thanks
Ollectrical

 

[telectrix]

your 9.6 for 1.5mm is wrong. should be 11.9.

, which makes the frunking facror 1585, so trunking size comes out @ 100 x 50.

 

[Ollectrical]

You sir, are a hero. You have my up most thanks

 

[soms]

Just looking over this for some revision and I am curious as to why the factor 9.6 is incorrect when the OP has stated the cables are single-core, thermosetting cables with stranded conductors?

 

[btvc-electrical]

Looking at the osg I also see the 1.5mm² coming in at 9.6. I am wondering if the mistake is in the 45% rule.