If these are part of Machinery as defined in the Supply of Machinery (Safety) Regulations, then this his a moot point, because the standard is BS EN 60204-1 not BS 7671 ... and this applies to all of the control wiring and power out to the motors. BS 7671 stops at the incoming mains supply to the Machinery. Test parameters may well be different - for example on the protective bonding circuit continuity is a different test entirely to the continuity of protective conductors test in BS 7671.

More to the point, the manufacturer's recommendations apply.

The duty holder should have the relevant information to maintain the Machinery under the relevant legislation (including PUWER and Section 6 of the H&S@Wetc Act.

HVAC is 'Machinery' as defined (this was clarified a number of years ago), but can also apply to other motors if they are doing something that comes under the definition of 'machinery'.

The extent of 'Machinery' includes the controls as well as the parts actually performing the process or movement.

Auryn Morgan said:

Some consultants are suggesting otherwise which on the face of it doe not appear a reasonable approach.... they are even suggesting that the control wiring is a requirement. 

If it is determined that the control wiring comes under BS 7671, this is absolutely the case, they are either LV, FELV, SELV or PELV circuits and ought to be tested accordingly ...

Just to add to this, the reference in BS7671 is 110.2 (xi) which excludes machines covered by BS EN 60204.

And the scope for BS EN 60204 states;

"This part of IEC 60204 applies to electrical, electronic and programmable electronic
equipment and systems to machines not portable by hand while working, including a group of
machines working together in a co-ordinated manner"

"The equipment covered by this part of IEC 60204 commences at the point of connection of the
supply to the electrical equipment of the machine"

"This part of IEC 60204 is applicable to the electrical equipment or parts of the electrical
equipment that operate with nominal supply voltages not exceeding 1 000 V for alternating
current (AC) and not exceeding 1 500 V for direct current (DC), and with nominal supply
frequencies not exceeding 200 Hz"

Just to add to this, the reference in BS7671 is 110.2 (xi) which excludes machines covered by BS EN 60204.

And the scope for BS EN 60204 states;

"This part of IEC 60204 applies to electrical, electronic and programmable electronic
equipment and systems to machines not portable by hand while working, including a group of
machines working together in a co-ordinated manner"

"The equipment covered by this part of IEC 60204 commences at the point of connection of the
supply to the electrical equipment of the machine"

"This part of IEC 60204 is applicable to the electrical equipment or parts of the electrical
equipment that operate with nominal supply voltages not exceeding 1 000 V for alternating
current (AC) and not exceeding 1 500 V for direct current (DC), and with nominal supply
frequencies not exceeding 200 Hz"