320.80 Ampacity.

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In MA, the 90°C rating of a type AC cable is not permitted to be used for ampacity adjustment and correction calculations.

MA amendments.

320.80(A)(1). Delete the last sentence of the first paragraph, which reads: “The 90°C (194°F) rating shall be permitted to be used for ampacity adjustment and correction calculations; however, the ampacity shall not exceed that for a 60°C (140°F) rated conductor.

Code language as amended in Massachusetts:

320.80(A) Thermal Insulation.

(1) General. Armored cable installed in thermal insulation shall have conductors rated at 90°C (194°F). The ampacity of cable installed in these applications shall not exceed that of a 60°C (140°F) rated conductor. ~~The 90°C (194°F) rating shall be permitted to be used for ampacity adjustment and correction calculations; however, the ampacity shall not exceed that of a 60°C (140°F) rated conductor.~~

Click here to see the Massachusetts amendments to the 2026 NEC^®.

320.80 Ampacity.

Below is a Real Question from our Electrical Continuing Education Courses for Electrical License Renewal:

Which of the following is true regarding Type AC cable as amended in Massachusetts?

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	A:	The 90°C (194°F) rating shall be permitted to be used for ampacity adjustment and correction calculations; however, the ampacity shall not exceed that of a 60°C (140°F) rated conductor.
	B:	Armored cable installed in thermal insulation shall have conductors rated at 75°C.
	C:	Armored cable installed in thermal insulation shall have conductors rated at 60°C.
	D:	Armored cable installed in thermal insulation shall have conductors rated at 90°C (194°F).

320.80 Ampacity.

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320.80 Ampacity.