Hey Kalle,
Any large money transfer between accounts has the chance to be spied or investigated. However, if you've never had a history of bans or investigations into your account, you're LIKELY (disclaimer: no method is ever 100% safe, as is the life of botters) to be safe. I've transferred far larger amounts between main and alternate accounts before with no issues.
BIG DISCLAIMER: Know the risk involved in anything related to bot activity. If you care a lot about this main account, it might not be wise to transfer the money, even if you have an arbitrarily low chance of detection. It's all a roll of the dice. I am by no means an expert in this field, but has been casually botting (1-2 toons active at a time) since Cata, and I think my experience can at least help to answer a question like this.
Tomtebow got a reaction from Bambo in Getting gold to my main account. Help!