question

xben avatar image
xben asked

Chassis ground of not chassis ground...

Hi!

I'm in the process of installing the Phoenix 1200VA in my RV. In the installation manual, it is suggested to jump the Neutral to the protective earth internally, then to connect the protective earth (stud) to the vehicle chassis.

Currently, my RV has a generator and the shore power connections has potential AC input power, all being switch manually, by plugging the power cord to the desired power source. I will follow the same idea for the The Victron inverter, adding an extra power inlet.

In the RV, the battery negative as well as the generator neutral and shore power neutral are all connected to the vehicle chassis. My concern is that, when using the generator or the shore power, its neutral will also be connected to the Victron inverter neutral. Would this hurt the device or am I overthinking this?

Thanks!

Phoenix Inverter
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2 Answers
Kevin Windrem avatar image
Kevin Windrem answered ·

The rule is that the neutral and PE connection should be made at the source of power and nowhere else. This connection provides a path for hot to chassis fault currents and will cause the circuit breaker to trip for safety. Without this connection, the safety ground network could be elevated to the voltage on the hot lead and pose a fire or electrocution risk.

Check out Wiring Unlimited for lots more useful info:

https://www.victronenergy.com/media/pg/The_Wiring_Unlimited_book/en/theory.html

There is also a PDF version somewhere.


Shore power neutral should NOT be connected to PE/safety ground. That bonding is upstream of the receptacle you plug into.

Bonding the generator's neutral to PE depends on whether that connection is made inside the generator or not.

The neutral to PE connection inside the Phoenix SHOULD be made since it is the source and would otherwise not have a neutral/PE bond.

When switching between shore, generator and inverter power, you need to switch the hot and neutral, not just the hot. This is a safety issue so that faults don't feed power back into the shore power plug. It's also the only way to adhere to the one PE/neutral connection rule.

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xben avatar image
xben answered ·

electrical-setup.png

In the picture, there is a Male Plug and 3 female receptacles, in which the Male plugs into one of them at a time. The Male plug does not have a connection between Neutral and chassis. The generator does have one, and the inverter would also have one. Once connected to the shore (camping post, house, etc) or the into the generator, the RV now does have a neutral/PE connection upstream.

In this situation, the inverter HOT is floating (in his female receptacle), but his neutral/PE connection is still there, connected to the shore or generator neutral/PE link.

In this situation, should I install a switch to break the inverter neutral/PE link to the vehicle chassis (see picture)?

Thanks!


electrical-setup.png (22.2 KiB)
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Kevin Windrem avatar image Kevin Windrem commented ·
NO!! NEVER disconnect PE connections !!!!!

All the PE connections can be connected together at all times. You show this in your drawing but not the one for shore power. The shore PE will be connected to your system PE when plugged in, but I'd still connect the shore PE to your system PE.

NEVER connect shore power PE to neutral. This IS done upstream and a second connection is not permitted.

As I said previously, the generator may bond the PE and neutral internally. If not, the best place to do so is at the generator before any cabling.

Same for the inverter. Use the internal jumper then keep PE and neutral separate everywhere.

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xben avatar image xben Kevin Windrem commented ·
To recap...


  1. Generator neutral/PE is done at generator before its female receptacle. Verified
  2. Shore neutral/PE is done upstream. Verified
  3. Inverter neutral/PE is done inside inverter. Will do
  4. I can leave the inverter PE/neutral/chassis connection even when using other power sources.

Thanks!

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