Why only 170 Vac between the 2 live conductors

Can you provide more detail as to where these conductors are? Is this in a home, an industrial setting, or ?

Please let us know what country you are in.

How long is the cable run?

What size breaker is on the feed side of the circuit?

What is the circuit for?

What size are the conductors within the cable?

From main fuse box 20 Amp mcb to fuse spur to run barriers in car park in uk

The low voltage can be caused by several reasons, loose or open neutral, corroded connection, defective connection or breaker, too many reasons possible to be specific here.

Need to call in an electrician to trouble shoot the circuit and system.