Modifying strange 3 way switch wiring

Question

Just moved into a house, and wanting to replace one of the 3 way switches with this item:

zwave switch

From what I can tell the two switches each have three wires in them, well 4 incl ground. They both have:

Common / Neutral (white wire) Traveler (red wire) Ground (copper wire)

One switch has Line - current is always flowing through it. One switch has Load - current is only available depending on the switch position.

So two questions:

1) Is it normal that Line and Load are on two separate switches?

2) Based on the diagrams for the product, is there a way that I can wire the new switch to get it to work with my setup?

I tried adding line with the load to the new switch, and taking it off the other switch i.e. new switch has everything, then the other switch only has the traveller and the common, per the diagram. However that was no good.

I'm not 100% sure how the lights are wired, I can't access them easily.

Thank you!

edit - product wiring images (better quality in the link above):

Answer 1

Is it normal that Line and Load are on two separate switches?

Yes the Line hooks to the first switch and the Load can come from the 2nd switch.. With Travelers between the two switches.

I am guessing your whites are really black taped whites (or should be) they are not Neutrals - again a guess otherwise how will the light work with out a hot line ? So either there are more wires or you have whites that should have been taped black on the ends.

That said your Zwave most likely requires the Neutral and from what I understand the NEC code for the neutral in the switch box is fairly new (2011 ish) . Sometimes they were run in the box just because that was where everything connected so you ended up with it by 'accident' and not by code. You should check your boxes and see what wires are behind those switches and not just look at what is connected on the terminals ..

Your normal layout would be

Answer 2

With only 3 wires plus ground you don't have a neutral on an existing 3 way switch. You have a hot. I was taught on switch legs to run the white as the always hot. Then you have 2 travelers until recent code changes this was the red and black and the ground bare / green wire. I have seen so many different ways to wire 3 ways over the years many that were code violations it would be hard to describe them all but for a mechanical spdt switch combination to work the 3 wires are required, just because you have a white wire don't assume it is a neutral especially with a home that is 20+ years old. If you don't have access to the wiring how can you rewire it would be my concern.

Answer 3

The picture with a yellow background is the easiest way to run wire for a 3 way switch. This way there is only two wires in each box (for our purposes here let's pretend this circuit is the only one in existence and no other switches or jumpers are involved), and one wire to the light. Nothing else is required to make the three way functional. The neutral goes through each box, which meets the new code requirement. Forget the color of each wire. A 3 way switched circuit needs an incoming hot on the common screw of one of the switches, a hot going to the light on the common screw of the other switch, and two traveller wires running between the two brass screws of the switches. The light needs a hot from one switch and a neutral. This method of wiring satisfies all these conditions with the bonus of having a neutral in each box. There are several ways to wire a three way switched circuit. Not all of them leave a neutral in each box. You can bring power to the light first, a common method of wiring all switches years ago, and the neutral stops there.
Another bonus to this method is the ease in which a 4 way can be added to the circuit. Just put a 4 way switch in between the two 3 way switches. The travellers from one 3 way switch go on two similar colored screws of the 4 way, and the other travellers go from the second 3 way to the other similar colored screws on the 4 way.