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Having some difficulty with breaker/fuse placement.

smoothJoey said:
@beckkl please acknowledge that you understand the significance of the neutral/ground bond and how its relates to mobile applications with shore power.
Click to expand...
Not entirely, but let me take a crack at it:

I think there was an outstanding question as to whether the MPP will switch the neutral bond if on shore power vs not, correct? As in the neutral would be bonded to the chassis when on battery, but not if on shore power. Is the idea that if I had an ATS I could bond the NC inverter input neutral to the chassis?
 
beckkl said:
Not entirely, but let me take a crack at it:

I think there was an outstanding question as to whether the MPP will switch the neutral bond if on shore power vs not, correct? As in the neutral would be bonded to the chassis when on battery, but not if on shore power. Is the idea that if I had an ATS I could bond the NC inverter input neutral to the chassis?
Click to expand...

Regardless of how its implemented the idea is...
The neutral/ground bond must be in only one place.
When you are connected to shore power the neutral/ground bond is somewhere upstream of the pedestal.
When your are not connected to shore power the neutral/ground bond is within your domain(likely the mpp unit).
For both states the outlet circuit tester should not show a floating neutral or any other error for that matter.

This is for life safety and fire protection.
 
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smoothJoey said:
Regardless of how its implemented the idea is...
The neutral/ground bond must be in only one place.
When you are connected to shore power the neutral/ground bond is someone upstream of the pedestal.
When your are not connected to shore power the neutral/ground bond is within your domain(likely the mpp unit).
For both states the outlet circuit tester should not show a floating neutral or any other error for that matter.

This is for life safety and fire protection.
Click to expand...
I don't think the MPP would be able to handle this. In the manual they reference:

1591898897139.png

I would think I could simply bond the neutral of the inverter output AC to the chassis if I go the ATS route, since there would be no scenario where there the inverter would be active when on shore power.
 
beckkl said:
I don't think the MPP would be able to handle this. In the manual they reference:

View attachment 15220

I would think I could simply bond the neutral of the inverter output AC to the chassis if I go the ATS route, since there would be no scenario where there the inverter would be active when on shore power.
Click to expand...

Can't be sure without knowing the details of the ATS.
 
smoothJoey said:
Sounds like you know what you are doing so I'm not going to worry.
Be careful though.
Click to expand...
I'll probably set everything up on a table outside first and get out the trusty outlet tester, see where things shake out. Thanks for the help.
 
beckkl said:
I'll probably set everything up on a table outside first and get out the trusty outlet tester, see where things shake out.
Click to expand...

Be careful: Some inverters have a power saving 'hunt' mode where they turn off the AC after a time of no load. While in this state they occasionally send out a pulse to see if a load appeared. If they detect a load they immediately turn on the AC. This is great for saving power, but a 'trusty outlet tester' is no longer so trusty. It can indicate no power present when the inverter is in the power saving mode. Then when you touch the circuit because you think it is safe, the inverter decides you are a load that needs full voltage.....Zap!?
 
FilterGuy said:
Be careful: Some inverters have a power saving 'hunt' mode where they turn off the AC after of time of no load. While in this state they occasionally send out a pulse to see if a load appeared. If they detect a load they immediately turn the AC. This is great for saving power, but a 'trusty outlet tester' is no longer so trusty. It can indicate no power present when the inverter is in the power saving mode. Then when you touch the circuit because you think it is safe, the inverter decides you are a load that needs full voltage.....Zap!?
Click to expand...
Well, I suppose that a lesson for not ensuring the wire cannot be live :)
 
smoothJoey said:
Sounds like you know what you are doing so I'm not going to worry.
Be careful though.
Click to expand...
Well, no dice on the ATS helping with the neutral bonding issue. Because Both the inverter and shore power are technically both providing power to the swtich, the bonding I did in the box on the inverter side trips the GCFI on the house. I'm thinking of bonding the neutral and ground in the RV panel with a NC relay wired to the shore power. I think that might be a simpler solution, and less expensive.
 
beckkl said:
Well, no dice on the ATS helping with the neutral bonding issue. Because Both the inverter and shore power are technically both providing power to the swtich, the bonding I did in the box on the inverter side trips the GCFI on the house. I'm thinking of bonding the neutral and ground in the RV panel with a NC relay wired to the shore power. I think that might be a simpler solution, and less expensive.
Click to expand...

I don't know how your ats works.
Which wires does it switch?
 
smoothJoey said:
I don't know how your ats works.
Which wires does it switch?
Click to expand...
Hot and neutral. But its on a delay of 15 or so seconds. I bonded the neutral of the output of the MPP unit but this trips the shore power GFCI breaker when it is plugged in.
 
Is this what you implemented?
diysolarforum.com

Having some difficulty with breaker/fuse placement.

I purchased the 12V 1K MPP Solar unit for my camper, and am having trouble determining fuse/breaker sizing and placement. I will have 160W of panels and a 100AH AGM battery. My understanding is that I need about a 125A fuse on the positive of the battery, but the manual also mentions that the...
diysolarforum.com diysolarforum.com
 
Here is another option.

tpdt = triple pole double throw

Code: 
                     inverter_charger->|        |->master_breaker
                                        ->tpdt->
shore_power->surge_protector->breaker->|        |->master_breaker
 
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I'm trying to avoid switching anything manually. A NC relay that breaks the neutral bond when energized from shore power seems like the simplest solution?
 
beckkl said:
I'm trying to avoid switching anything manually. A NC relay that breaks the neutral bond when energized from shore power seems like the simplest solution?
Click to expand...

I think it will work and I'm a big fan of simple.
 
Relay worked perfectly. The neutral bond in the RV panel is broken when shore power is present. GFCI breaker in the RV trips with the tester when on battery power, and the GFCI breaker in the garage trips when on shore power. Much simpler solution than the ATS and about $70 less. Now I have to put everything together nicely so it doesn't look like this:

1592334594722.png
 
Did you also test with an outlet tester?
Should be fine but if you have one its worth doing.
 
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