Quiet line test has mains hum - how to fix

Question

My BT incoming pair is located right below the electrical mains distribution board.
A Quiet line test has main hum which goes away when I trip the RCDs (there are two)
My speed has never been good (2.5Mb max - we are nearly in the next exchange area), but speed is now only 1.5 since we recently had to have an RCD replaced for safety reasons.
My immediate neighbour syncs at 2.4Mb using a different pair in the same drop wire.
I've been testing direct from the incoming pair - NO house wiring connected at all, so forget i-plate issues.
I conclude the mains hum is my primary problem.
What minimum separation distances and layouts are needed to eliminate mains interference?
I believe phone & power should cross at 90 deg and not run parallel - what are the rules?
Can I shield the existing phone wiring (with kitchen foil or something. I guess it will need earthing or something)?
The phone wiring disappears into structure at the edge of the cupboard (the same side as the incoming mains power!!) and can't be pulled thro or easily changed.
There is a little slack to mount the master socket etc a bit lower
Can one post a photo on this forum to show what I mean?
Any Help would be much appreciated
Graham S

Answer 1

Photo of electrical board and BT Master socket layout
Mains units (L to R)
1. Off peak clock
2. House RCD
3. Live junct. box
4. Meter
5. Incoming mains
Below is phone board
with new External supply with RCD
L to R
Box 1. Solwise filtered phone point (used as Junct box)
Box 2. BT Master with test socket in use
3. External supply Dist box with RCD + 2 breakers
Cabling:
BT line in is White sheath from lower right of picture
An UNFILTERED BT line pair goes to router;
A filtered pair returns in the same 4 core phone cable
feeding all house phone wiring from the Solwise
rear terminals (Box 1)
Clearances:
BT Master to External dist box: ~ 50mm horizontally
BT Master to live Mains tail: 220mm vertically
Phone cables have to run at RH side, near incoming mains.
My HomeHub 2 stats:           My semi-detached neighbour (from same drop wire)
Sync 1,440 down, 448 Up     2,432 / 448
Noise 15.1 / 13.0                 6.4 / 13.0
Attentuation 62.0 / 31.5       61.2 / 13.5
Power 16.6 / 12.4               3.8 / 1.3
IP Profile 1.27 / 0.45           (not taken)
Question:
The PC & the router are on a power bar, which I have regularly turned off overnight
(well after the initial BBand burn-in period)
Have I shot myself in the foot by doing this?
Graham S