The offer increases the pressure on US rival Emerson Electric which failed to win the company's support in April with a takeover proposal worth 723m.
Chloride employs 2,300 people in 15 countries, of which 374 are located at bases in the UK including Aberdeen.
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Hide AdABB said Chloride's strength in the area of uninterruptible power-supply systems gave it a leading presence in a field where it is not active.
The Swiss bidder is a specialist in power and automation technologies that enable utility and industry customers to improve their performance. It has 117,000 staff and operates from more than 20 locations in the UK, employing 2,300 people.
Emerson Electric's rejected offer was worth 275p a share, compared to the 325p a share in yesterday's recommended offer from ABB.
Emerson issued a brief statement confirming it was considering its response in the wake of ABB's agreed takeover deal.
Shares in Chloride closed up 56p at 344.5p.