Hot water heater not working on Generator?

[rustybucket]

Ok, so odd thing we just realized the last couple trips. Our hot water heater doesn't seem to be working on the generator. Works great on shorepower, but nothing on generator.

Both the water heater and generator were new and un-tested when we bought the boat. I did a google search and it seems like it maybe an un-bonded neutral issue? Water heater is 240v.

Anyone have any ideas of how to correct this issue? Do I just tie the ground and neutral together at the water heater?

 

[Boatsb]

Id look at what was done to install it. Ive seen people who installed 220V units on the 110 wires and just switched wired but that could be dangerous.

First identify what the wiring is connected to and determine the next step from there.

 

[Pascal]

I had a similar issue when i got my boat where the dryer would not work on generator. It became a non issue when i replaced the stack with a 120v all in one.

I am about to reconnect the generator to the new panel and now with 220v chillers and cooktop... it better work.

A few days ago i checked the output on the generator terminal and have 240 across the hots so i assume something had been miswired when the generator was replaced by a previous owner around 2002

I believe Ground and neutral are usually bonded at the generator (and inverter when inverter is in inverter mode). On shore power, ground and neutral are bonded shore side. That said, i dont see how not having them bonded would affect the water heater which is basically just a 240v heating element and doesnt require neutral

 

[Briankinley2004]

Have you checked other 240 volt circuits to make sure they work on generator?

 

[rustybucket]

Have you checked other 240 volt circuits to make sure they work on generator?

Yup, everything else seems to work great. Washer/Dryer/Stove/AC units...etc.

 

[Boatsb]

I had a similar issue when i got my boat where the dryer would not work on generator. It became a non issue when i replaced the stack with a 120v all in one.

I am about to reconnect the generator to the new panel and now with 220v chillers and cooktop... it better work.

A few days ago i checked the output on the generator terminal and have 240 across the hots so i assume something had been miswired when the generator was replaced by a previous owner around 2002

I believe Ground and neutral are usually bonded at the generator (and inverter when inverter is in inverter mode). On shore power, ground and neutral are bonded shore side. That said, i dont see how not having them bonded would affect the water heater which is basically just a 240v heating element and doesnt require neutral

Ground and neutral should not be bonded on the shore side.

That would be incredibly dangerous.

Ground on the shore side should never be attached to anything--but ground

 

[Pete]

Not sure if there is confusion on split phase neutral grounding (how our 240 volt boats are wired), but the shore power center tap neutral (white wire) will be grounded at the source of the shore feed to the boat, usually at the central breaker panel on shore. Look for the grounding rod at this location.

As the general case ALL sources of electric power are to establish a ground reference, at the shore feed main breaker, the generator frame, and the inverter frame. The electric source selection switches/breakers then connect the neutrals along with the hots.

 

[Pete]

I should have mentioned that on Hatteras' with isolation transformers, the shore power is wired different, as the white wire neutral from shore is not brought to the boat. The red and black hots plus the green wire ground are attached to the boat. The green wire stops at the shore power inlet plate and grounds this plate for safety. The red and black hots then attach to the shore power isolation primary winding and the neutral to ground wire polarizing is done using a secondary center tap on the secondary of the transformer, which is correctly treated as the source for shore power on the boat.

 

[Boatsb]

Not all our boats are 240 volt and not all have transformers.

A standard 2 x 120 volt system or a 240 volt system without a transformer can not have ground and common together on the shore side.

Transformers change things. I have isolation transformers on my ground. That's the only transformer many smaller vessels have.

 

[Pete]

Going back to the OP question. Suggest first checking the voltage with a multimeter at the heating element on the water heater first on shore power and next on generator power. Note any difference. If you get zero on both cases, temporarily turn the thermostat higher on the water heater until you get voltage on shore power, then check the generator power. Return the thermostat to its original setting once you have your results..

 

[Pete]

Not all our boats are 240 volt and not all have transformers.

A standard 2 x 120 volt system or a 240 volt system without a transformer can not have ground and common together on the shore side.

Transformers change things. I have isolation transformers on my ground. That's the only transformer many smaller vessels have.

A 2 x 120 setup has the same grounding characteristics on shore power as a 240 boat without a transformer. The white wire in each 120 service is connected to the same buss bar back at the shore main breaker, which is the same buss bar for the white wire on a 240 shore feed, which is the same as the white wire on an isolation transformer that is left unconnected at the boat inlet.

On the green wire ground "isolation transformer" you mention and the competing technology of reverse bias diodes, that is a completely different subject in my mind, so I will not comment.

 

[Boatsb]

Unconnected or unused on many boats with transformers. It not to be common to the ground on the shore side. That's what I was trying to explain.

Per code the neutral must be intact and separate from the ground on the shore side. As its brought into boats with transformers the neutral can be left off the system as the transformer will create the 2 120 volt legs with its neutral.

 

[MadHatter53]

Two pages and no one asked why your heating hot water.

 

[Avenger]

Two pages and no one asked why your heating hot water.

That's funny right there, I don't care who you are.

 

[Pete]

The green ground wire and the white neutral wire remain separate for safety reasons until the wires terminate on shore at the source of the power where the grounding rod is buried at which both the green ground and white neutral are joined together within a foot or two of attachment to the earth grounding rod. The reason for this is to prevent the green safety wire from acting as a parallel neutral back to the earth ground rod, and in rare cases putting voltage on the green wire. Boats without isolation transformers therefore should keep the white neutral and the green safety separated on the boat when on shore power, but should tie the white and green together for alternate sources of power, at the source of power, including a generator and inverter.

How to protect your boat and yourself from bad actors on other boats in a marina, that can compromise the integrity of the green wire is also an important subject.

 

[Boatsb]

How hot is hot enough?

Could he need steam?

 

[jim rosenthal]

Maybe he's cleaning the carpets. Didn't we have a thread on that recently?

 

[Pascal]

The green ground wire and the white neutral wire remain separate for safety reasons until the wires terminate on shore at the source of the power where the grounding rod is buried at which both the green ground and white neutral are joined together within a foot or two of attachment to the earth grounding rod. The reason for this is to prevent the green safety wire from acting as a parallel neutral back to the earth ground rod, and in rare cases putting voltage on the green wire. Boats without isolation transformers therefore should keep the white neutral and the green safety separated on the boat when on shore power, but should tie the white and green together for alternate sources of power, at the source of power, including a generator and inverter..

This is what i meant by shoreside earlier in this thread. G and N are bonded at the source which is either shorepower, generator or inverter in inverter mode. That is why when not inverting marine inverters release the bond...