Progressive Industries EMS and Surge Guard fault codes
A hardwired or portable unit between the pedestal and the coach. It reads voltage, frequency, polarity and ground, drops the contactor on a fault, and holds power off for a delay so the AC compressor can bleed down. A fault code on the box is a reading of the pedestal and cord, not of the coach, until you prove otherwise with your own meter.
Progressive EMS code E-0
Normal, power passing. Nothing to fix. If the coach is still dead, the problem is downstream: transfer switch, main breaker, or the cord between the EMS and the panel.
Progressive EMS code E-1
Reverse polarity: hot and neutral swapped. Meter the pedestal yourself: hot to ground should read about 120V, neutral to ground near 0V. If it is swapped the park wiring or a homemade adapter is wrong. Do not bypass.
Progressive EMS code E-2
Open ground. Meter hot to ground at the pedestal. 0V means no ground path and the EMS will not pass power. Check the adapter and cord ends for a broken ground pin before blaming the park.
Progressive EMS code E-3
Line 1 high voltage, above 132V. Also what you get when a 30A coach is fed 240V through a miswired pedestal or adapter; the display shows 240. Never bypass for this one. Meter the pedestal and move sites if it is the park.
Progressive EMS code E-4
Line 1 low voltage, below 104V. Meter the pedestal with no load, then with the AC running. Big sag under load is pedestal or cord voltage drop: hot plug blades, a long or undersized extension, or a park at capacity on a hot afternoon. Shed load.
Progressive EMS code E-5
Line 2 high voltage, above 132V (50A only). Same checks as E-3 on the second leg. L1 high with L2 low at the same time is an open neutral: stop and find it before anything else runs.
Progressive EMS code E-6
Line 2 low voltage, below 104V (50A only). Same checks as E-4 on the second leg. If only one leg is low under load, the park has a weak leg or the pedestal breaker is cooked.
Progressive EMS code E-7
Frequency high, above 69 Hz. Almost always a generator or inverter, not the grid. Check the generator governor and RPM; a portable generator running fast does this.
Progressive EMS code E-8
Frequency low, below 51 Hz. Generator loaded down or governor off. Measure Hz at the generator outlet under load; 58 to 62 Hz is the target.
Progressive EMS code E-10
Surge module used up. The MOVs took hits and are spent. The unit still manages power but has no surge protection left. Replace the module or unit.
Progressive EMS: Display dark, no power
Open neutral (no code for it). On 30A the display stays dark and power is refused. On 50A an open neutral shows up as one leg high and the other low. Check the neutral pin on the plug and the pedestal lugs.
Surge Guard: Open ground
No ground at the pedestal or in the cord. Meter hot to ground at the pedestal. Check the ground pin on the plug and adapter.
Surge Guard: Reverse polarity
L1 or L2 landed on neutral or ground. Pedestal or adapter wiring. Do not run the coach on it.
Surge Guard: L1 high / L2 high
Above 136V on that leg. Pedestal problem or open neutral. Meter both legs to neutral.
Surge Guard: L1 low / L2 low
Below 102V on that leg. Voltage drop or a weak park. Meter no-load and loaded.
Surge Guard: L1 amps / neutrip
Current over 110% on a leg, or neutral over 130% (50A). Too much load, or on 50A a coach wiring problem putting both legs on one side. Check the panel for a double-fed neutral.
Surge Guard: Recept overheat
Plug or receptacle running hot. Look at the plug blades and the pedestal receptacle for burning and loose contact. Replace the plug end; a hot pedestal receptacle is the park's repair.
Surge Guard: GND high
Voltage on the ground conductor. Something upstream is leaking to ground. Unplug and meter ground to a known earth. Report it to the park.
Surge Guard: Open neutral
Neutral lost on the coach side. Check the neutral at the inlet, the transfer switch and the panel neutral bar.
Surge Guard: Replace surge
Surge protection expended. Unit still switches power but the MOVs are gone. Replace.
Learn the system
- Shore power: 30A vs 50A
- Breakers, GFCIs and the EMS
- The lost neutral (50A danger)
- Transfer switches and generator power
Practice it on a service call
Guided diagnosis
Full field guide: Progressive Industries EMS and Surge Guard
Codes come from the maker manuals and public service sheets. Your model's own chart always wins, and LP and 120 volt work belongs to a qualified technician.