Advice needed for electric pedestal tester

pianotuna wrote:
I generally dial down the input amperage to 80% of the rated value. (24 amps on a 30, 12 amps on a 15). I don't "dial down" when plugging into a 50 amp source, as I have a break out box that extracts one 30 amp and two 20 amp circuit breaker protected outlets.

I always run from a 30 amp campsite drop and do manage our power draw so we never pull beyond 20 amps. This past season I paid particular attention - easy to do with the Progressive EMS monitor panel mounted within easy view inside the camper - and never once saw total draw exceed 18 amps. Runs to the campsite power post here in the Ontario provincial park system are typically quite long so although I carry 140' of main service cable I most frequently find I can reach the post with 75' of cable. With a maximum 20 amp draw that translates to a maximum voltage drop of ~ 3 volts ...



... so assuming a properly sized park electrical system I've got quite a bit of latitude before low voltage becomes an issue. Nonetheless, I have several times each season (usually during July & August when everyone is running A/C) had my Progressive EMS do what it's designed to do - disconnect when incoming voltage under load drops below 104 vac. For me, this occurrence isn't yet sufficiently frequent to justify investing in a voltage regulator ... eventually perhaps, but for now I'm happy to have my Progressive EMS simply disconnect. :B

Hi S.G.

The vast majority of owners simply plug in, ems or not.

The only issue I have run into is low voltage. My first attempt to "fix" that was a Magnum hybrid inverter/charger. Much to my dismay, I found out that "load support", while extremely useful, is NOT voltage support.

I generally dial down the input amperage to 80% of the rated value. (24 amps on a 30, 12 amps on a 15). I don't "dial down" when plugging into a 50 amp source, as I have a break out box that extracts one 30 amp and two 20 amp circuit breaker protected outlets.

Now, I have the Sola Basic autoformer which I've upgraded with a surge device, and my low voltage woes are finally over.

I've never seen loss of ground.

pianotuna wrote:
Hi J-d,

That is why I load the outlet with a 1500 watt device when I'm testing.

Since you didn't quote what it is j-d said that you're referring to I'm guessing you mean his last statement - "We still don't know if a pedestal breaker has "gone soft" but at least we won't burn something out or get shocked, if we lead off with a Tester." :h

If this is what you're referring to I guess I can see your point - load the circuit as you test to emulate the load your rig itself might place on that circuit. However, I've not once had my Progressive EMS connect if there was anything amiss ... the only reason I even bother with a tester is so that if that source does turn out to have some sort of issue I don't waste my time and effort dragging out multiple lengths of main service extension cable, which here in Ontario can often be over 100'. Most times that turns out to be a "make work" project 'cause the power source almost always proves to be acceptable, at least when I first plug in ... most of the errors I run into seem to occur later on - most often low voltage, sometimes accompanied by loss of ground. I've never detected frequency issues and have yet to run into a mis-wired pedestal but maybe I've just been lucky. :D All that said I am getting lazier and lazier as each season comes around and am more likely in future to just not bother pretesting at all but to simply plug in and let my Progressive EMS do what it's designed to do, automatically, with no effort on my part ... and likely what the vast majority of EMS owners also do. :D

j-d wrote:
It's clear from the context of the question, and from the responses, that it's 30-Amp service in question. The plug-in using Adapter, Polarity Tester and AC Meter are the way many of us go.

There IS a thread somewhere about a home made 50-Amp tester. It's two of the 30-Amp in most ways, connected to a 50-Amp plug, but with a big difference. This one looks at the polarity of the two 50-Amp legs that make up this service, and verfies there's a Neutral. That's important to anybody who plugs into a 50-Amp outlet. Whether it's a 50-Amp coach, or just the rest of us using a 50-to-30 Adapter.

I don't want to plug in, let alone even back in, till I know that outlet is right! Campground can fix it, move me, or refund me.

We still don't know if a pedestal breaker has "gone soft" but at least we won't burn something out or get shocked, if we lead off with a Tester.

I sure can see the usefulness of a 50 amp pedestal tester in that situation. A guy could park in the driveway, go to his spot, and then test the pedestal before backing or pulling in.
Basically, a 50 amp tester is just a redundancy of the 30 amp tester. I guess a guy could have the two hot legs switched to test that each are functional. A three position switch combining the two legs could give an accurate view of voltage. An alternative would be to have two phase monitors to determine the connectivity of the two legs.

Hi J-d,

That is why I load the outlet with a 1500 watt device when I'm testing.

It's clear from the context of the question, and from the responses, that it's 30-Amp service in question. The plug-in using Adapter, Polarity Tester and AC Meter are the way many of us go.

There IS a thread somewhere about a home made 50-Amp tester. It's two of the 30-Amp in most ways, connected to a 50-Amp plug, but with a big difference. This one looks at the polarity of the two 50-Amp legs that make up this service, and verfies there's a Neutral. That's important to anybody who plugs into a 50-Amp outlet. Whether it's a 50-Amp coach, or just the rest of us using a 50-to-30 Adapter.

I don't want to plug in, let alone even back in, till I know that outlet is right! Campground can fix it, move me, or refund me.

We still don't know if a pedestal breaker has "gone soft" but at least we won't burn something out or get shocked, if we lead off with a Tester.

SoundGuy wrote:
Both of these statements infer that the Progressive EMS unit is using this 136" time delay to analyze the input signal before deciding it's stable enough to pass along to the trailer. This is incorrect as the analysis takes no time at all - ..... snip

time2roll wrote:
My question to Progressive:

Still curious on an intermittent error. If the voltage or ground briefly drops every 60 seconds does the EMS reset the timer at each error? Or does it connect at 136 seconds and wait for the next error before disconnect? Thank you

Today from Progressive:

If the voltage falls below 104 Vac for more than 6 seconds, the EMS will disconnect. A loss of ground will cause an instantaneous disconnect. When an error occurs and then the cause clears, the time delay starts. In your example, if the error occurs every sixty seconds, power would not be restored, because the delay would be resetting to zero each time.

My Comment: This is in effect monitoring of the connection for the entire 136 seconds. Power and connection must remain stable within specs for the entire delay timer or timer resets. I understand the effect is to have power off a minimum time for the air conditioner internal pressure to bleed down.

That wasn't my experience, even though this statement came from Progressive ... if input voltage to the EMS is reduced it will disconnect power to it's output the instant input voltage drops below 104 vac, not 6" later. I've demonstrated this with my own EMS on my workbench and DVMs connected to monitor both input and output voltage. However, there is a caveat to this - since I don't own or have ready access to a Variac I can use to externally draw down input voltage to the EMS the only way I can do this is use the trim pot within the EMS ... and when I do so the EMS does disconnect the moment voltage drops just slightly below 104 vac, not 6" later. Since I don't have a schematic of the EMS I can't say for sure whether the difference in methodology would impact the way the EMS behaves but lowering the voltage using the trim pot in the EMS did in my case trigger a disconnect immediately.

As for your comment about "monitoring", the EMS doesn't just monitor for 136" (or 15" in the case of a hard wire model with the jumper in place) but rather continuously, as in anytime it's seeing power applied to it's input. The EMS will disconnect anytime it detects an error in the incoming source or if the error is present when the unit is plugged in it won't connect at all, in which case it will display not only an E* error code but also a PE* error code. Once a disconnect then an eventual reconnect occurs delay timing starts again, just as one would expect ... so although I've read your previous comments several times about monitoring I'm not sure I understand what your concern is. :h The unit does what it's supposed to do - not pass on power to the trailer anytime it detects an error and will only reconnect (with the selected delay) once that error is no longer present. :B

As a FOOTNOTE to this ...

The more I think about it having the EMS wait 6" before it actually disconnects because of a low voltage situation does make sense as it would be an effective way to avoid nuisance disconnects when the source voltage was hovering just above and below the 104 vac threshold. Monitor any source voltage with a DVM and voltage, even when measured in just 1/10ths of a volt, will vary constantly 0.1 or 0.2 or 0.3 volts so I can see how one moment it might be 104.1 then swing to 103.9 and cause the EMS to disconnect if there was no delay ... annoying for sure if voltage otherwise would swing back above 104.0 volts a moment later. I wonder if this 6" delay is applied also in a high voltage threshold as well? :h This probably also explains why the hard wire versions have a minimal delay of 15" instead of none at all ... but what's the significance of 15", why not any delay greater than 6"? Hmmmmm. :h

Darn, sure wish I had a Variac so I could do some accurate testing. :R

Hi,

If the voltage drop caused by the air conditioner starting is below 110 volts, the Sola Basic autoformer boosts almost immediately to ten volts higher than the low (i.e. 108 becomes 118 volts)--perhaps in 1/10 of a second and certainly within a second. Once the voltage recovers from the start up, the Sola "drops out" of the circuit.

time2roll wrote:
Today from Progressive:

If the voltage falls below 104 Vac for more than 6 seconds, the EMS will disconnect.

My Comment: This is in effect monitoring of the connection for the entire 136 seconds. Power and connection must remain stable within specs for the entire delay timer or timer resets. I understand the effect is to have power off a minimum time for the air conditioner internal pressure to bleed down.

SoundGuy wrote:
Both of these statements infer that the Progressive EMS unit is using this 136" time delay to analyze the input signal before deciding it's stable enough to pass along to the trailer. This is incorrect as the analysis takes no time at all - ..... snip

My question to Progressive:

Still curious on an intermittent error. If the voltage or ground briefly drops every 60 seconds does the EMS reset the timer at each error? Or does it connect at 136 seconds and wait for the next error before disconnect? Thank you


Today from Progressive:

If the voltage falls below 104 Vac for more than 6 seconds, the EMS will disconnect. A loss of ground will cause an instantaneous disconnect. When an error occurs and then the cause clears, the time delay starts. In your example, if the error occurs every sixty seconds, power would not be restored, because the delay would be resetting to zero each time.



My Comment: This is in effect monitoring of the connection for the entire 136 seconds. Power and connection must remain stable within specs for the entire delay timer or timer resets. I understand the effect is to have power off a minimum time for the air conditioner internal pressure to bleed down.

SoundGuy wrote:
Both of these statements infer that the Progressive EMS unit is using this 136" time delay to analyze the input signal before deciding it's stable enough to pass along to the trailer. This is incorrect as the analysis takes no time at all - rather, delay is set at 136" in order to protect an A/C compressor, preventing it from restarting until head pressure has diminished to a safe level. Progressive EMS delay for the portable versions is fixed at 136" but delay for the hard wire versions can be shortened to a more convenient 15" by removing an internal jumper. I took this one step further with my own EMS-HW30C by wiring in an SPST switch in place of the jumper so I can simply switch between the two delay times, 15" or 136", rather than have to open the case and fool with the jumper. :B

time2roll wrote:
OK and say intermittent fault every 30 seconds. Does not the timer reset each time?
Or does PEMS just check the instant the timer expires and calls good or no?

The Progressive EMS automatically disconnects anytime it detects an error in the incoming service and will not reconnect until that error disappears. Whenever an error is detected output power is disconnected instantly and what is normally a blank cycle on the display will then show PE*, with * being a number representing the nature of the error, such as PE2 which means loss of ground. That previous error code remains until power feeding the unit is removed completely and then correct power (in this case with ground intact) is restored, in which case that PE* error code will be cleared and show blank again until such time as there may be another error. In a case where the EMS is initially plugged into incorrect power the unit will show an error code (such as E2) plus a PE* code (in this example PE2) and will never output power to the trailer until the error is removed or the unit is disconnected from source power and then plugged into power with no errors.

FWIW, I wired up a jig on my workbench so I could demo these various sequence of events, using loss of ground as my "error" as it's one of the most common I've run into, along with low voltage, but is one of the easiest to emulate by simply adding a switch in the ground wire feeding the EMS so it can easily be disconnected / reconnected, emulating an error in source power. None of this however has anything to do with the unit's time delay setting(s), of which the longer 136" delay exists solely for the purpose of allowing A/C compressor head pressure to diminish to a safe level before power is restored to the trailer.

Hopefully this clarifies how the Progressive EMS works. :)