2023 NFPA 70, 90.9(C) Permitted Uses of Soft Conversion

[GetWiredEmpire]

What does this mean and what are the practical applications of this code?

90.9(C) Permitted Uses of Soft Conversion.
The cases given in 90.9(C)(1) through (C)(4) shall not be required to use hard conversion and shall be permitted to use soft conversion.

(1) Trade Sizes.
Where the actual measured size of a product is not the same as the nominal size, trade size designators shall be used rather than dimensions. Trade practices shall be followed in all cases.

(2) Extracted Material.
Where material is extracted from another standard, the context of the original material shall not be compromised or violated. Any editing of the extracted text shall be confined to making the style consistent with that of the NEC.

(3) Industry Practice.

Where industry practice is to express units in inch-pound units, the inclusion of SI units shall not be required.

(4) Safety.
Where a negative impact on safety would result, soft conversion shall be used.

 

[GetWiredEmpire]

I think it just means that, where it's advisable for safety reasons, refer to the nearest SI unit to complete a task.

Article 90.9(D) Compliance
Conversion from inch-pound units to SI units shall be permitted to be an approximate conversion. Compliance with the numbers shown in either the SI system or the inch-pound system shall constitute compliance with this Code.

 

[Carultch]

I think it just means that, where it's advisable for safety reasons, refer to the nearest SI unit to complete a task.

Shouldn't the hard and soft columns be swapped in your table? I would expect exact conversions to be a hard conversion, and approximate conversions to be a soft conversion.

 

[GetWiredEmpire]

Shouldn't the hard and soft columns be swapped in your table? I would expect exact conversions to be a hard conversion, and approximate conversions to be a soft conversion.

That's a good observation. I got it from 2023 NFPA 70 and I think the code book could use an update or two.

It looks like the Public Input Submission Closing Date was set for September 7, 2023. So that's not good. I guess I will have to try to get into contact with the Committee another way.

 

[GetWiredEmpire]

That's a good observation. I got it from 2023 NFPA 70 and I think the code book could use an update or two.

It looks like the Public Input Submission Closing Date was set for September 7, 2023. So that's not good. I guess I will have to try to get into contact with the Committee another way.

Above the table is listed the explanation.

Article 90.9(D) Compliance
Soft conversions are numerically accurate. Hard conversions are rounded or approximate values of the customary unit dimension. Soft conversions are required when an approximation would negatively impact safety. The table below offers examples of the hard conversion process. The conversion of the U.S. customary units into metric equivalents shows the small variance between soft conversions and hard conversions.