While Fools should generally take the opinion of Wall Street with a grain of salt, it's not a bad idea to take a closer look at particularly stock-shaking upgrades and downgrades -- just in case their reasoning makes sense.

What: Shares of Eaton Corporation (NYSE:ETN) gained slightly on Friday after Nomura Securities initiated coverage on the diversified power company with a buy rating.

So what: Along with the bull call, analyst Shannon O'Callaghan planted a price target of $87 on the stock, representing about 20% worth of upside to yesterday's close. While momentum traders might be turned off by the stock's year-to-date pullback, O'Callaghan thinks that Eaton is too cheap to pass up given its strong competitive position and growth potential.

Now what: According to Nomura, Eaton's risk to reward trade-off is pretty attractive at this point. "Following its $13bn transformative acquisition of Cooper (December 2012), Eaton is a leading diversified power management company with both cyclical and operational earnings drivers," noted O'Callaghan. "Over 60% of segment profit now comes from Eaton's leading electrical businesses, while the balance comes from quality (though more cyclical) Vehicle and Hydraulics businesses and a solid Aerospace business." When you couple those positives with Eaton's forward P/E of 13 and 2%-plus dividend yield, it's tough to disagree with Nomura's bullishness.