[UK-CONTEST] Cables and Connectors

[G3SJJ]

Not sure if I should raise this in case the whingers say it should be 
banned!!  Anyway, I am gradually re-assembling my station back into the 
main shack after IOTA and have decided make some of the connections more 
"professional."

1 - I am using 9 way D Subs for rotator and relay control systems. Is 
there a screw fixing for a male/female pair so that they don't pull 
apart? I had a look in the local Maplins but couldn't see anything. The 
ultimate aim would be to have SO2R/Multi-op in either the main shack or 
the summerhouse (2nd shack!), or say Ft1kMP in main shack and K2 in 2nd 
shack.Standardised connectors would enable rapid selection of any of the 
options.

2 - I want to install the WX0B Sixpak at the base of my mast which will 
need about 90m of cabling. Currently the TopTen 6 way relay box is fed 
with 90m of heavy duty 7 way "trailer" cable. Instead of installing a 
second run of trailer cable, I thought about a single run of 14 way 
shielded cable but I am wondering if there will be too much voltage drop 
when two relays are selected. I did some calculations for the mains feed 
to the summer house based on the IEE listing (eg 37 amps, 10sq mm etc, 
and all the regulations) to get mains voltage drop so I understand all 
that but I am not sure about current ratings for 12v DC switching and 
the various cables.

My questions really are :
1 - Is this advisable? ie 1 run of 14 way screened instead of two x 7 
way heavy duty unscreened.
2 - Assuming say 100mA per relay, ie 200ma current drain, any 
suggestions on cable size and type?

Farnell stocks some .25 sq mil 14 way screened stuff, but I am not sure 
how this translates into voltage drop for a 90m run. It is also costly. 
I could take about a 2v drop. Just need a bit of guidance to get my mind 
round this.

Chris G3SJJ