One of those outlet testers rides in my "bag of tricks" that goes to every gig with me. I check outlets in every venue when I play there the first time, and also any time there is a problem (hum issues, shocks).
HOWEVER: it's important to know that there are faults one of these testers cannot detect. There was a recent discussion thread on another website where people talk about bass
involving such a problem that could have been life-threatening.
For those interested in the details - in the US, most outlets these days have three contacts: hot, neutral, and protective ground. The hot wire is 120 VAC, the neutral is nominally at 0 V (ground potential) and carries the return current that has passed through whatever load is plugged in, ground is also at 0 V, and is normally not supposed to carry current; it connects to (for example) the chassis of an amplifier and ensures that if somehow the hot wire shorts to the chassis it will trip a circuit breaker rather than energizing the chassis at 120 V. Neutral is bonded (connected securely) to protective ground at the breaker panel.
This is a relatively new standard (well, it seems new to someone at my age
). There are many older buildings that don't have the third ground wire running to all the outlets, just the hot and neutral. In this case, a three-prong outlet may bond the ground pin to the neutral
at the outlet. This is fine - as long as the wire presumed to be neutral really is neutral.
It goes badly wrong if somewhere the hot and neutral wires were crossed up. With old, non-polarized, two-prong outlets this didn't matter because anything could be plugged in either way (this is why old amps had a "polarity" switch), and you just had to hope nothing in your amp shorted to the chassis. But if hot and neutral are mixed up and the "neutral" (which is really hot) is connected to the protective ground, then your amp's chassis is now live at 120 V. A licensed electrician will (or at least should) check this; a home handyman may just know "black is hot, white is neutral, easy!" and not bother to verify this is true when upgrading an outlet.
The outlet tester can't detect this. The red light (indicating voltage between neutral and ground, shouldn't happen) won't light up because they're both at the same voltage (120 V). The two yellow lights come on, indicating voltage hot to neutral and hot to ground, because what should be hot is at 0 V and neutral and ground are both 120 V.
As far as the original question - no good answer here. If I were in the situation, I'd probably sigh and buy a whole new grow light, one not made in China
