Shielding for pmag wires

[tomhanaway]

Do any of the wires (12v or p-lead) require/benefit from shielding? I'm not talking about wires to sparkplugs, only the wires to panel.

No indication of such in emagair's wiring diagram. Nuckolls mentions shielding for magnetos but that's a somewhat different animal.

Thanks,
Tom H.

[N941WR]

No shielding is required. If you elect to add wires for the comm port into the cockpit, use twisted pair.

You can short the twisted pair together, which is the same as adding the jumper or connect to the P-mags with a PC using Emag's EICAD program to tune them or install an EICommander.

[tomhanaway]

Got it.
Thanks Bill.

[JohnInReno]

From page 7 of the current manual (114):

Note 1: If you are r
eplacing a magneto, your old P-Lead can serve this
purpose, and may already be wired to a
suitable switch. Take care that
magneto p-lead wire is shielded, and th
e shielded braid is a potential
(unintentional) short to
ground. Keep it clear of
connections and terminals.

I take this to mean that it is ok to use the existing p-lead in an upgrade, but make sure it is not inadvertently grounded.

[Gisnar]

When I replaced my mags with pmags, p leads were shielded. I just used the existing leads. No problems with mag operation or radio noise. So shielded cables work. Can not say about non shielded cables.

[N941WR]

Originally Posted by JohnInReno

...

I take this to mean that it is ok to use the existing p-lead in an upgrade, but make sure it is not inadvertently grounded.

Correct.

The way the standard P-mag wiring works is to power the P-mags up when the Master is turned on. Then the ignition switch grounds them, just like a standard mag. Grounded, no spark, ungrounded, spark.

The difference with the P-mag is that when the P-mags are powered up and grounded, they are in "setup mode". Meaning that you can blow in the tube and set top dead center when they are powered up and grounded.