Hi,
Me and a buddy of mine, is building a EA to trade foreign exchange in MT4, and to make this system as consistent as possible, we are planning to diversify the money between 10-15 non-correlated pairs.
Since many people in this forum probably have more experience then we do in assembling portfolios, we though that you might give us a helping hand.
Does anyone have a list 10-15 non-correlated yet, liquid pairs?
Helpfull replies will be much appreciated. 
There are only seven major currencies. That means if you’re looking at 10 pairs you’re going to have to use pairs that include several currencies at least twice. Add in to the mix that EUR and CHF are extremely closely correlated and that GBP isn’t far off and you are presented with quite the challenge to come up with that many non-correlated pairs.
Let’s say we want to have more than seven pairs in our portfolio, how would you rate the liquidity of the mentioned minor currencies?
Are there any I[/I] differences(vs. major?)?
There can be massive differences. All you need to do it look at the size of the bid/offer spread to see how liquid or illiquid a pair is. More liquid pairs have tighter spreads. They also tend to be fairly active 24-hours vs. others that are decidedly more regional in their trading patterns. If your trading approach is going to be short-term in nature, then those spreads are going to be very important.
Our trades have a range from everything between 1-2 days to a few months.
Neither of us currently have a live account with a forex broker, what would you (rhody) say is a normal spread for a pair outside of the majors?
(normal market conditions)
Do you think you could please be so kind as to rank the top 15 or 20 most liquid pairs in the fx market?
We’ll try to sort out the correlation issue ourselves, and if we don’t, we will probably come running back, begging for help here. 
The broker I plan to use offer low spreads, (4 or less) on 8 currencies. EUR, USD, JPY, AUD, CAD, GBP, CHF, NZD
You can make 4 uncorrelated pairs from this:
NZD/USD
AUD/JPY
EUR/CAD
GBP/CHF
Based on a recent review of Oanda spreads (taken mid-morning Eastern time), here are the pairs with spreads of 5 pips or less listed from lowest to highest:
EUR/GBP
EUR/USD
EUR/CHF
USD/JPY
AUD/USD
EUR/JPY
GBP/USD
NZD/USD
USD/CAD
USD/CHF
CHF/JPY
EUR/DKK
USD/INR
CAD/JPY
AUD/JPY
EUR/CAD
GBP/CHF
GBP/JPY
USD/SAR
USD/SGD
You’ll notice some non-majors in the list (DKK, INR, SAR, SGD), but the narrowness of the spreads suggests that these are the most liquid pairs.
GBP/JPY was at 4 pips when I grabbed those figures. Looking right now at nearly 2pm Eastern I see 6.5 pips. Same for GBP/CHF. EUR/DKK right now is 6 pips.
All depends on your timeframe and trade frequency. If I’m holding for days to weeks, I could care less about the spread. If I’m trading in and out all day long, then you bet it makes a difference!
Thank you very much guys! This was very helpfull.