How is the Speakon connector wired for REL sub?

Al, I was just getting ready to wire it up and thought I'd check here first. Whew, glad I did. I was a little concerned as the amp is dual mono configuration.
Can I check the amp's negative terminals for continuity to ground with a meter? Or check for continuity between the negative terminals? Thanks.

I looked at the back of the amp and there is a large ground lug, actually looks exactly like the speaker binding posts except it's not gold. There is no continuity between the ground and the speaker terminals. Also, no continuity between the speaker terminals.
Thanks so much for posting Al.

Can I check the amp's negative terminals for continuity to ground with a meter? Or check for continuity between the negative terminals?

I was about to post the following response when I saw your subsequent post, which makes this no longer relevant. But I'm submitting it anyway, as an fyi:

I'd feel very confident that doing either of those things won't hurt anything, but I'm hesitant to say that with 100.00% confidence.

What you could do instead, as a temporary connection arrangement to confirm that signals are present on the amp's - output terminals, would be to connect the + inputs of the sub to the - terminals of the amp (for each channel), and one of the - inputs of the sub to the ground screw on the back of the amp. If you hear sound from the sub with those connections, it would confirm that signals are present on the amp's - output terminals.

Best regards,
-- Al

I'll try that tomorrow. Decided to hold off hooking it up until tomorrow. If I blow something up I'll be up all night thinking about it.
Thanks again for your valuable help here.

Built the cable and decided to try it out on my Harman Kardon HK6350 integrated amp instead of the Primare. The cable works fine. My thanks to BRF and Almarg for the assist.