Another MEP-802 standby generator thread

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rcamacho

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Bainbridge Island Wa
Sharing progress on my project to connect a MEP-802a to the home for backup power.

Infamous well nut fix. Recommend starting with this first. My genset worked great however leaked after a few weeks.


Electrical panel interlock installed. This required adjusting position of all breakers a bit. New 30A dual pole breaker in upper left position.



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mcii

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When where will these then become bonded, your saying remove the bonding furnished strap typically already connected between ground and neutral ? While its not hard to do, I am confused ? thanx mac/mc
 

Chainbreaker

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When where will these then become bonded, your saying remove the bonding furnished strap typically already connected between ground and neutral ? While its not hard to do, I am confused ? thanx mac/mc
Your breaker panel in your house is where it is already bonded. Therefore, you do not want to have another bond at the generator, that is unless you are using the generator as a self derived system (standalone with driven ground rod connected to generator, like when using at a remote location).
 

Scoobyshep

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When where will these then become bonded, your saying remove the bonding furnished strap typically already connected between ground and neutral ? While its not hard to do, I am confused ? thanx mac/mc



The way you are setup (BTW awesome job with the interlock) the generator and the house both have the neutral and ground tied together (bonded). Since your interlock does not perform a switching action on the neutral the neutral and grounds are in parallel. this can lead to current being present on the generator frame. Hooked up to the house remove the strap from the ground to generator neutral. If you ever disconnect it from the house then make sure that strap gets reconnected.
 

rcamacho

Member
247
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Location
Bainbridge Island Wa
The way you are setup (BTW awesome job with the interlock) the generator and the house both have the neutral and ground tied together (bonded). Since your interlock does not perform a switching action on the neutral the neutral and grounds are in parallel. this can lead to current being present on the generator frame. Hooked up to the house remove the strap from the ground to generator neutral. If you ever disconnect it from the house then make sure that strap gets reconnected.
Yep,
I’ll be running 10gauge 4 wire to the L14-30 plug. Since. I’ll be disconnecting the bonding strap since the unit will be connected to panel ground.


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mcii

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Thank you Chainbreaker, this is precisely the discussion I was trying to promote, wherein the set is operating as a stand alone operation or as a supply source to a remote location. These operational settings/locations are very different and need to be treated as such. We can't just make a stand alone all situations statement with no distinction being made between operational settings or environment/s..
best: mac/mc
 

Scoobyshep

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Yep,
I’ll be running 10gauge 4 wire to the L14-30 plug. Since. I’ll be disconnecting the bonding strap since the unit will be connected to panel ground.


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That will work. Just remember to re bond it if it is ever used in a different configuration.
 

rcamacho

Member
247
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Location
Bainbridge Island Wa
Finished NM-B wiring from panel interlock to an L14-30 generator input. Access was a bear as sheetrock had to be removed to drill through a stud and route cable into the panel.



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Last edited:

rcamacho

Member
247
20
18
Location
Bainbridge Island Wa
Test run complete
I can run the whole home without any significant load.
Oven and dryer no problem.
Heat pump can run at 100-110% load provided I shut off some lights and any other high amp loads.

Used the opportunity to load bank the set for about 40m

https://youtu.be/WeHmMQBo9lo


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Last edited:

rcamacho

Member
247
20
18
Location
Bainbridge Island Wa
Addendum:
Interlock and wiring fully approved/inspected
Added the code required tie down for back-feed breaker. Additionally added a surge suppressor to the panel.






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builmord

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Location
dungannon, va
if your system main bonding jumper, connection of grounded conductor with grounding conductor, is located in your house service panel, first means of disconnect, why can't your power supply from the generator use 3 conductors, two hots and a neutral similar to the utility feeder that attaches to your house. both of these sources would have a jumper connecting the metal enclosures they are in to the neutral to protect from shock . the ground rod attachment would also be connected at this point. this set up would eliminate parallel current flow and still provide short circuit protection for the generator and its frame and the installation using a 3 conductor cord would cost less
 

rcamacho

Member
247
20
18
Location
Bainbridge Island Wa
if your system main bonding jumper, connection of grounded conductor with grounding conductor, is located in your house service panel, first means of disconnect, why can't your power supply from the generator use 3 conductors, two hots and a neutral similar to the utility feeder that attaches to your house. both of these sources would have a jumper connecting the metal enclosures they are in to the neutral to protect from shock . the ground rod attachment would also be connected at this point. this set up would eliminate parallel current flow and still provide short circuit protection for the generator and its frame and the installation using a 3 conductor cord would cost less
Interesting.
For a 240V installation up to 30A my research on this forum, TM, code, other sources pushed me towards the current design.

I’m happy with the external L14-30 input for the MEP-802 or other portable generators in this class. It gives me flexibility to connect a wide range of equipment.

3 conductor run may save some $ but that was not a primary concern. I saved at least $1k performing the work.


Bond strap is disconnected per TM. 10/4 ground is not switched only hot lines are at breaker


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builmord

Member
46
1
8
Location
dungannon, va
is your connection to the breaker on your house panel through a 30 amp 4 wire receptacle which is connected to the generator via your 10/3 with ground cord ? this would rely on the house panel to bond the generator neutral and frame. If you started the generator to use the gfci receptacle on the unit without having the house panel plugged in where would the ground be for the gfci to function properly
 
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