Wire size for 220 spindle

[Aiph5u (Aiph5u (not affiliated with Onefinity))]

Hey Kenneth,

it depends on what cable do you mean, the VFD input cable on a single-phase input VFD has usually much stronger cross-section area, while on the spindle cable, which is a shielded 3+PE cable at the output of the VFD, you have the power spread over the three wires, each sinus wave shifted by 120°.

These informations have to be read in the VFD manual. For my 2.2 kW 220 V single phase input VFD I use 2+PE x 4.0 mm² (recommended: 10 AWG) and for the spindle cable I use…

@Aiph5u

…shielded 4 x 2.5 mm² (3+PE) (approx. AWG13) (LAPP cable No. 0026271)

@Aiph5u

Note that in engineering, wires are not measured in wire diameter (as in American wire gauge), but in cross-section area, because the cross section of a wire is directly proportional to its strength and weight, and inversely proportional to its resistance. The cross-sectional area is also related to the maximum current that a wire can carry safely. Wire diameter rp. AWG is not.

There is a nice Comparison chart for American Wire Gauge to IEC 60228 in this file:

• Comparison of SWG (red), AWG (blue) and IEC 60228 (black) wire gauge sizes from 0.03 to 200 mm² to scale on a 1 mm grid – in the SVG file, hover over a size to highlight it

For the VFD output which is the spindle cable, …

@Aiph5u

…I use LAPP ÖLFLEX® CLASSIC FD 810 CY, in the strength 4 x 2.5 mm² (LAPP #0026271) for the 2.2 kW spindle or 4 x 1.5 mm² (LAPP #0026251) for a 1.5 kW spindle (=shielded 3+PE).

@Aiph5u

• On the output of the VFD, i.e. the spindle cable, you should use shielded 3+PE for the three-phase spindle, like shown here:

Image 1: A typical spindle cable for use in a power chain (LAPP ÖLFLEX® CLASSIC FD 810 CY)

See this thread for more information.

@Aiph5u

Note that even if PE wire and cable shield are both connected to ground, they serve two different purposes. PE is crucial for electrical safety, and shield cannot replace the PE wire!

Therefore the reference to “16/3” in the topic’s title is dangerous: NEVER connect a spindle without a PE wire ! Shield cannot replace a PE wire!

@Aiph5u

Also you should know that on chinese spindles, the power rating is often wrong (see here for example).

Note that should you really buy one of these cheap chinese kits, you should → read this to make your life easier.

@Aiph5u

You can buy Daniel Moran’s @PwnCNC ready-to-use spindle cable here.