There are a number of websites that explain how Scientific notation
can be made into Engineering notation by calling for 3 digits to the
left of the decimal place
000.0E+00 or ##0.0E+00
This website
http://people.stfx.ca/bliengme/ExcelTips/EngineeringNotation.htm
says that this format produces "poor results for numbers less that
1,000" and suggests using
[<0.001]##0.00E+0;[<1000] #0.00;##0.00E+0
Ignoring for a moment that they are missing a "#" in the middle
format, I do not see the "poor results". The formats in this table are:
Value #,##0.00000000
Scientific 0.00E+00
Eng1 ##0E+0
Eng2 [<0.001]##0E+00;[<1000]##0E+00;##0E+00
Eng3 [=0]0E+00;##0E+00
Value Scientific Eng1 Eng2 Eng3
0.00000100 1.00E-06 1E-6 1E-06 1E-06
0.00001000 1.00E-05 10E-6 10E-06 10E-06
0.00010000 1.00E-04 100E-6 100E-06 100E-06
0.00100000 1.00E-03 1E-3 1E-03 1E-03
0.01000000 1.00E-02 10E-3 10E-03 10E-03
0.10000000 1.00E-01 100E-3 100E-03 100E-03
0.00000000 0.00E+00 000E+0 000E+00 0E+00
1.00000000 1.00E+00 1E+0 1E+00 1E+00
10.00000000 1.00E+01 10E+0 10E+00 10E+00
100.00000000 1.00E+02 100E+0 100E+00 100E+00
1,000.00000000 1.00E+03 1E+3 1E+03 1E+03
10,000.00000000 1.00E+04 10E+3 10E+03 10E+03
100,000.00000000 1.00E+05 100E+3 100E+03 100E+03
1,000,000.00000000 1.00E+06 1E+6 1E+06 1E+06
10,000,000.00000000 1.00E+07 10E+6 10E+06 10E+06
100,000,000.00000000 1.00E+08 100E+6 100E+06 100E+06
1,000,000,000.00000000 1.00E+09 1E+9 1E+09 1E+09
It looks like Eng1 and Eng2 are identical.
Eng3 adds a condition to format zero better.