EMS works TOO well

Boomerweps · 09-21-2018, 10:43 PM

While installing my extra 15 Amp inlet and receptical today, I figured I could use some AC. EMS shut down power within a few seconds of turning on the AC.
Undervoltage error code. With AC off and EMS reset, voltage at 114VAC. My previous reading on the Kill-A-Watt were 107.7VAC with just the AC on. EMS undervoltage supposed to be at 105VAC. My best estimate is I have a total of 120 feet of 12AWG from House CB box to TT inlet. Yup, a good voltage drop, I know.

**Bama Rambler** · 09-22-2018, 07:19 AM

Sounds like your EMS did exactly what it was supposed to do. I'd say it likely saved your A/C.

**KyDan** · 09-22-2018, 07:57 AM

Put the EMS in bypass for a test.
Get a volt meter and check the voltage
at your rig while the AC is running.
Some here have reported their EMS was reading lower voltage than they actually had.
Just to be sure you know what's really going on.

Boomerweps · 09-22-2018, 08:32 AM

Quote:

Originally Posted by KyDan

Put the EMS in bypass for a test.
Get a volt meter and check the voltage
at your rig while the AC is running.
Some here have reported their EMS was reading lower voltage than they actually had.
Just to be sure you know what's really going on.

Don't have a bypass mode, that's on the remote display model AFAIK. Considering getting more 10awg wire and wiring in some plugs for a bypass. Of course that means 2 plugs and 2 jacks and the $ roll up ;(

I ran out after the storm last night and checked the garage outlet, 117.3vac. I need to check both that and the TT EMS at the same time this AM.

I had problems when the TT was powered through 190' of combined 12awg cable before (100.7 w/ AC, 112.5 w/o) no probs at 50' (110.4 w/ AC, 117 w/o), no previous probs (pre EMS) with its current 90' location (107.7 w/AC, 117 at garage outlet, add 30' cable from there). At each of these locations I took readings with and without AC & fridge on. EMS currently reads 114 with AC off, supposed to shut down at 105.

CedarCreekWoody · 09-22-2018, 08:52 AM

There was a thread last week where someone's EMS had an inaccurate voltage reading, causing it to trip prematurely. There was a post in the thread about how to adjust it.
But you should realize that you are running dangerously close to dangerously low voltage. You should strongly consider going to heavier gauge cable for the long run.

Boomerweps · 09-22-2018, 09:21 AM

Quote:

Originally Posted by CedarCreekWoody

There was a thread last week where someone's EMS had an inaccurate voltage reading, causing it to trip prematurely. There was a post in the thread about how to adjust it.
But you should realize that you are running dangerously close to dangerously low voltage. You should strongly consider going to heavier gauge cable for the long run.

Concur. This AM I ran a few voltage checks. 120.5vac at dogbone on TT per Kil-A-Watt (KAW), EMS 123v at idle .32A load. AC did not want to pull much power, outside temp is 55F. Ran microwave instead. 16A overall load, 112.5v KAW, 113EMS. Back at idle 121.1 KAW, 124 EMS. So if anything, the EMS reads high. This is a one person running in and out of the TT test so the values could change in transit ;(.
I'm likely going to try to find and rent a Trencher come spring and run some 8AWG buried cable almost straight from near the house CB box to the preferred TT parking spot beside the garage. Easier than trying to run even 10AWG through the pipe with the current 12AWG going to the garage and I can make the run about 30 percent shorter than the 12 is. Then the garage will get a 30TT jack with CB.

CedarCreekWoody · 09-22-2018, 10:18 AM

If you are starting this circuit from an adequate panel I would suggest you consider running 6 gauge cable and installing a pedestal with 20/30/50 amp outlets and breakers. A bit more expense now but much easier than redoing it all "just in case" you later upgrade to a 50 amp RV.

Boomerweps · 09-22-2018, 10:48 AM

Quote:

Originally Posted by CedarCreekWoody

If you are starting this circuit from an adequate panel I would suggest you consider running 6 gauge cable and installing a pedestal with 20/30/50 amp outlets and breakers. A bit more expense now but much easier than redoing it all "just in case" you later upgrade to a 50 amp RV.

Yes, THAT is a consideration.

CedarCreekWoody · 09-22-2018, 02:58 PM

Quote:

Originally Posted by Boomerweps

Yes, THAT is a consideration.

"I will never trade up." Famous last words. We made it one year before upgrading. Lol

tooclose · 09-23-2018, 12:24 PM

I run a 50 amp system. The factory cable is 5 gauge Your 8 my work but why take the chance

Boomerweps · 09-23-2018, 01:50 PM

Quote:

Originally Posted by tooclose

I run a 50 amp system. The factory cable is 5 gauge Your 8 my work but why take the chance

The 8awg is for a 30amp service. I'd use 6awg if planning on a 50amp service. But in local discussions, somebody brought up using 8/3 vice 8/2 (ground not counted on install wire). That way I could have dual 30 amp service, one for the TT and one for upgrading the garage to 30 from 20amp. Also, it could provide dual 30 amp to a 50 amp future RV. If using the 6awg, I'd have to use 6/3 and that's a lot of copper ($$). The 8/3 would give me options for now and in the future not be too limiting at a reasonable (for the function) cost.

Bottom line: while I want sufficient TT power at home to use as a guest house, maybe enough in a real emergency if the house was unlivable, I'm not looking for a full camping stand alone level system. This is all in the development phase for next spring.

Boomerweps · 10-12-2018, 11:34 AM

Now when I hooked up to the current 20amp in the garage after camping the EMS discovers no ground on several of the outlets. I have to open up and check the quad box in the garage ;(

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