Sprinter-Forum    
 

Go Back   Sprinter-Forum > Sprinter-Based RV's & Conversions > Sprinter RV's & Conversions Talk

Sprinter RV's & Conversions Talk Common features found in Sprinter RV's and Conversions.


 
Thread Tools Display Modes
Old 01-24-2020, 04:31 AM   #61
Kevin.Hutch
2011 Mercedes 313 906
 
Kevin.Hutch's Avatar
 
Join Date: Sep 2013
Location: Mackay Qld Aus
Posts: 227
Thanks: 11
Thanked 76 Times in 64 Posts
Default Re: 2 inverters?

Quote:
Originally Posted by john61ct View Post
All of these complications are moot

if you do not wire mains power circuits and outlets.

I like to keep things simple:

99.9% of consumption is direct DC, no inverters

any AC load devices plug directly into their inverter

if there were an AC outlet, it would be impossible for it to be fed by more than one inverter

the only thing fed directly from shore power or the genset is the charger, and that just physically plugs in

if I had electric aircon, it would also plug in like the charger, but likely to a separate AC circuit or genset from the charger
100% correct, if the charger is the more common transformer type the isolation is guaranteed if one device is connected to one power source at a time, be it generator or inverter there is no problem.

The complication is when multiple devices are powered at once and a ground connection is introduced, the interconnection issues begin via the common connection.

Most generators or inverters do not have an internal connection between one of their live wires and the frame/ground/earth and often these three are at not the same voltage, so by definition, there is no return path for a GFCI detection to activate ie no protection.

The only way I know to detect a Ground Fault in this situation is to measure the voltage between the live wires and earth and if either exceeds 40volts it can be potentially lethal.
__________________
Kevin Hutch
MB 2011 diesel NCV3 313 (906 635) 4325mm (170") WB high roof 651955 2143 95kw engine
Talvor 2012 conversion Rego 2013.
Be part of the solution not part of the problem
Kevin.Hutch is online now   Reply With Quote
Old 01-24-2020, 04:41 AM   #62
Kevin.Hutch
2011 Mercedes 313 906
 
Kevin.Hutch's Avatar
 
Join Date: Sep 2013
Location: Mackay Qld Aus
Posts: 227
Thanks: 11
Thanked 76 Times in 64 Posts
Default Re: 2 inverters?

Quote:
Originally Posted by AirJoseph View Post
40 years in the electrical industry and I can't figure out what you guys are talking about.

My inverter feeds a small 120 volt breaker box. The neutral is connected to the enclosure at this location only. This is called the bonding of the neutral. All metallic parts of the van are also bonded to this location via bond wires in the cables. That's it. No connection to earth/ground is required as the electricity is separately derived in the van. This way, the breakers will trip when a hot wire makes contact with any of the metalic parts of the van. Yes, the GFCI receptacles will also work with this set up. The ground connection is only to provide a path for lightning or static electricity anyways. Use a piece of rubber dragging on the ground to dissipate that if it's a problem. Shore power connection to the van is what complicates things as the shore power should be bonded back at it's source. I prefer to use the shore power to only feed my battery charger thus avoiding any multiple path issues. In other words, never connect the van 120v panel to shore power, keep it isolated. I always use the batteries/inverter/battery charger when on shore power.
Clearly done by an experienced household and/or industrial electrician and 100% correct and the transformer of most battery chargers gives perfect isolation.

The gotcha as you say is if you wanted to alternate shore power to devices in the van (maybe a future owner) the neutral bond would trip a shore power GFCI necessitating the neutral bond be switched out. Readily done with a 'break before make changeover' but the earth GCFI required neutral bond would be lost when the shore power is unplugged without switching.
__________________
Kevin Hutch
MB 2011 diesel NCV3 313 (906 635) 4325mm (170") WB high roof 651955 2143 95kw engine
Talvor 2012 conversion Rego 2013.
Be part of the solution not part of the problem

Last edited by Kevin.Hutch; 01-24-2020 at 04:43 AM.
Kevin.Hutch is online now   Reply With Quote
Old 01-24-2020, 05:07 AM   #63
Kevin.Hutch
2011 Mercedes 313 906
 
Kevin.Hutch's Avatar
 
Join Date: Sep 2013
Location: Mackay Qld Aus
Posts: 227
Thanks: 11
Thanked 76 Times in 64 Posts
Default Re: 2 inverters?

Quote:
Originally Posted by OrioN View Post
Just like water, electrons circle or flow in the opposite direction in Auz, or south of the equator....
No unlike popular belief we are held down by the same gravitational pull too, the only difference is that our phase to neutral voltage is 230 (We use to be 240 until recently) and our convention is to have the active or hot pin clockwise from the earth when looking at a socket, also our active/neutral pins are 45% to the earth not horizontal like the US.

We commonly have red active/Hot and black neutral instead of Black active/hot and white neutral although we have adopted the international Brown active/hot, blue neutral convention but not retrospectively and many boats here are imported from the USA.

20 years working for an American computer company designing and installing computer rooms plus standby power systems, followed by many years in boats taught me a lot about the differences in US and Aus power and a healthy respect for earth leakage as well as ways to detect and protect.
__________________
Kevin Hutch
MB 2011 diesel NCV3 313 (906 635) 4325mm (170") WB high roof 651955 2143 95kw engine
Talvor 2012 conversion Rego 2013.
Be part of the solution not part of the problem

Last edited by Kevin.Hutch; 01-24-2020 at 06:47 AM.
Kevin.Hutch is online now   Reply With Quote
Old 01-24-2020, 06:44 AM   #64
AirJoseph
 
AirJoseph's Avatar
 
Join Date: May 2018
Location: Vancouver, Canada
Posts: 639
Thanks: 160
Thanked 78 Times in 63 Posts
Default Re: 2 inverters?

The gotcha as you say is if you wanted to alternate shore power to devices in the van (maybe a future owner) the neutral bond would trip a shore power GFCI necessitating the neutral bond be switched out. Readily done with a 'break before make changeover' but the earth GCFI required neutral bond would be lost when the shore power is unplugged without switching.

Unless you are willing to test that the shore power supply has it's polarity and bonding correct, then disconnect your power panel neutral bond each time you arrive at a camp ground, it's not safe using shore power directly. Even if you have everything wired correctly, your neighbor camper may not and could heat up your bond etc... It's just better to isolate.

Remember, electricity seeks all paths back to it's source. You don't want to be one of the paths....

I used to be responsible for two Marina's in the city and witnessed all kinds of electrical horror shows from boaters who 'diy wired their boats' including burning their boats down to the water line.

Last edited by AirJoseph; 01-24-2020 at 06:46 AM.
AirJoseph is offline   Reply With Quote
Old 01-24-2020, 06:50 AM   #65
AirJoseph
 
AirJoseph's Avatar
 
Join Date: May 2018
Location: Vancouver, Canada
Posts: 639
Thanks: 160
Thanked 78 Times in 63 Posts
Default Re: 2 inverters?

Quote:
Originally Posted by Kevin.Hutch View Post
No unlike popular belief we are held down by the same gravitational pull too, the only difference is that our phase to neutral voltage is 230 (We use to be 240 until recently) and our convention is to have the active or hot pin clockwise from the earth when looking at a socket, also our active/neutral pins are 45% to the earth not horizontal like the US.

We commonly have red active/Hot and black neutral instead of Black active/hot and white neutral although we have adopted the international Brown active/hot, blue neutral convention but not retrospectively and many boats here are imported from the USA.

20 years working for an American computer company designing and installing computer rooms plus standby power systems, followed by many years in boats taught me a lot about the differences in US and Aus power and a healthy respect for earth leakage as well as ways to detect and protect.
Just out of curiosity, what's your standard three phase voltage phase to phase? 50 or 60hz?

Thanks

Joe
AirJoseph is offline   Reply With Quote
Old 01-24-2020, 09:03 AM   #66
Bob Laps
 
Bob Laps's Avatar
 
Join Date: Aug 2017
Location: Raleigh,NC
Posts: 644
Thanks: 502
Thanked 233 Times in 151 Posts
Default Re: 2 inverters?

Man....this is complicated
__________________
Bob
2017 3500 ext
Bob Laps is offline   Reply With Quote
Old 01-24-2020, 10:39 AM   #67
Kevin.Hutch
2011 Mercedes 313 906
 
Kevin.Hutch's Avatar
 
Join Date: Sep 2013
Location: Mackay Qld Aus
Posts: 227
Thanks: 11
Thanked 76 Times in 64 Posts
Default Re: 2 inverters?

Quote:
Originally Posted by AirJoseph View Post
The gotcha as you say is if you wanted to alternate shore power to devices in the van (maybe a future owner) the neutral bond would trip a shore power GFCI necessitating the neutral bond be switched out. Readily done with a 'break before make changeover' but the earth GCFI required neutral bond would be lost when the shore power is unplugged without switching.

Unless you are willing to test that the shore power supply has it's polarity and bonding correct, then disconnect your power panel neutral bond each time you arrive at a camp ground, it's not safe using shore power directly. Even if you have everything wired correctly, your neighbor camper may not and could heat up your bond etc... It's just better to isolate.

Remember, electricity seeks all paths back to it's source. You don't want to be one of the paths....

I used to be responsible for two Marina's in the city and witnessed all kinds of electrical horror shows from boaters who 'diy wired their boats' including burning their boats down to the water line.
We are clearly on the same page, I fully agree isolation from other's power issues is the best option when sharing a power source having the only shore powered device the battery charger is an excellent compromise.

Isolation transformers of adequate capacity to run aircon and fridges are bulky, heavy and expensive so rarely used, but still the best option.

Here in Aus we have had double pole RCD plus double pole switches mandatory in all mains powered mobile accommodation (boats, caravans, campers, motorhomes and portable buildings) plus marina and trailer park outlets for many years so isolation is a lesser safety issue here.

Now we are seeing isolated power gensets and inverters commonplace as portable power sources and the mandate of a neutral ground connection before the RCD, is ignored.

I have replaced the RCD in my motorhome with a Residual Voltage Device that detects either the earth neutral presence or a voltage less than 40v live to ground, isolating the circuit within milliseconds.

This video shows the advantages of this approach; https://youtu.be/-Z6x5yZTXcc
__________________
Kevin Hutch
MB 2011 diesel NCV3 313 (906 635) 4325mm (170") WB high roof 651955 2143 95kw engine
Talvor 2012 conversion Rego 2013.
Be part of the solution not part of the problem
Kevin.Hutch is online now   Reply With Quote
Old 01-24-2020, 10:45 AM   #68
Kevin.Hutch
2011 Mercedes 313 906
 
Kevin.Hutch's Avatar
 
Join Date: Sep 2013
Location: Mackay Qld Aus
Posts: 227
Thanks: 11
Thanked 76 Times in 64 Posts
Default Re: 2 inverters?

Quote:
Originally Posted by AirJoseph View Post
Just out of curiosity, what's your standard three phase voltage phase to phase? 50 or 60hz?

Thanks

Joe
Our phase to phase is 415v and all our AC is 50hz
__________________
Kevin Hutch
MB 2011 diesel NCV3 313 (906 635) 4325mm (170") WB high roof 651955 2143 95kw engine
Talvor 2012 conversion Rego 2013.
Be part of the solution not part of the problem
Kevin.Hutch is online now   Reply With Quote
The Following User Says Thank You to Kevin.Hutch For This Useful Post:
AirJoseph (01-24-2020)
Old 01-24-2020, 03:48 PM   #69
AirJoseph
 
AirJoseph's Avatar
 
Join Date: May 2018
Location: Vancouver, Canada
Posts: 639
Thanks: 160
Thanked 78 Times in 63 Posts
Default Re: 2 inverters?

Quote:
Originally Posted by Kevin.Hutch View Post
Our phase to phase is 415v and all our AC is 50hz
Odd voltage. In the US standard 3 phase motor's come in 208 or 480 volts and here in Canada, we use 208 or 600 volts.
AirJoseph is offline   Reply With Quote
Old 01-24-2020, 03:58 PM   #70
rollerbearing
 
Join Date: Jan 2015
Posts: 2,113
Thanks: 711
Thanked 1,117 Times in 765 Posts
Default Re: 2 inverters?

Quote:
Originally Posted by Bob Laps View Post
Man....this is complicated

It is and it isn't. You will not have any problems if you properly install a transfer switch so that power can only come from a single source (big inverter, small inverter, shore power) at a time.

Proper installation includes consideration of the neutral/ground bonding issues of the sources and that is not that difficult when dealing with single (at a time) sources.
rollerbearing is online now   Reply With Quote
The Following User Says Thank You to rollerbearing For This Useful Post:
avanti (01-24-2020)

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump



All times are GMT. The time now is 11:24 PM.


Powered by vBulletin® Version 3.8.9
Copyright ©2000 - 2020, vBulletin Solutions, Inc.