At a recent stop in Albuquerque, our Surge Guard portable would not pass power to the coach. I checked the pedestal with a voltmeter. It looked OK to me.
Hot to Hot 240V
Each Hot to Neutral 120V
Neutral to Ground 0V
I did not check frequency.
My recollection is that the Surge Guard initially passed power, but then faulted. After that, it would not flash the delay lamp. The delay lamp normally flashes red during a 135 startup delay, then turns green when the unit starts passing power.
I thought the Surge Guard had failed, so I plugged the coach to the pedestal. All circuits worked fine and I saw no problems. Since then I have used the Surge Guard at home and at a shop in NAC. It seems to be good.
What am I missing?
Which model Surge Guard do you have? Info on their website should tell you the conditions which would cause the unit to not pass power. Newer units have more indicator lights or even an LCD to show what the unit detects:
Surge Guard RV Power Protection | Technology Research Corporation (http://trci.net/products/surge-guard-rv)
Also, what were the line voltages reported by the coach after you plugged in without the Surge Guard? It could have been either a low (<102 Vac; most likely) or high (>132 Vac; unlikely) voltage condition once the loads of the coach were connected. If the campground service was marginal, you could see 120/240 on the power pole with just a meter, but when the load of the coach was attached, it caused the voltage to droop sufficient for the Surge Guard to cut power. I suspect this since initially power was passed, then it dropped (things turned on in coach) and the Surge Guard didn't restart (IOW - it was still detecting a low voltage or other fault condition)
Our Surge Guard is about 4 1/2 years old. The indicators are pretty much go/no go. There is a red light showing voltage on each leg. There is another light that flashes red during time delay, then turns green if all is well. My recollection is that it did not light at all after the first drop out.The voltmeter at power monitoring station showed normal. However, it only shows one leg.
Indeed, there could have been a low voltage situation under load. A dirty connection could cause the problem I observed. Thanks for suggesting that possibility.
I plan to pay closer attention to all indicators, conditions, and measurements if this happens again. Fortunately, I can see no harm from the incident and I didn't buy another protection device to replace one that is apparently not broken.