20 amp Shore power OK?

[N147JK]

I "downgraded" from 30 amp to 15 so as to rid myself of having to carry around that gigantic 30 amp cable. Exchanged the main AC breaker from 30 to 15. 15 amps is way more than we'll ever need.

[Twoxentrix]

N147JK If you only have a 12awg (15amp) extension cord hooked up to a 15amp 110v home outlet, I don't understand the need to exchange the 30amp breaker with a 15amp?

[N147JK]

Originally Posted by Twoxentrix

N147JK If you only have a 12awg (15amp) extension cord hooked up to a 15amp 110v home outlet, I don't understand the need to exchange the 30amp breaker with a 15amp?

The breaker is there to protect the 15 amp cable. Most campgrounds provide 30 amp power, which of course I never want to see on my 15 amp cable. So for added safety, the breaker limits the entire system to 15 amps so I don't have to worry about an overload.

[posplayr]

Originally Posted by N147JK

I "downgraded" from 30 amp to 15 so as to rid myself of having to carry around that gigantic 30 amp cable. Exchanged the main AC breaker from 30 to 15. 15 amps is way more than we'll ever need.

Originally Posted by N147JK

The breaker is there to protect the 15 amp cable. Most campgrounds provide 30 amp power, which of course I never want to see on my 15 amp cable. So for added safety, the breaker limits the entire system to 15 amps so I don't have to worry about an overload.

........................

N14tJK's logic makes perfect sense. I just simplified what is spread out in a couple of posts.

For N14tJK's loads, anything above 15 amps is a fault so he limited the extension chord (for space weight savings) and breaker (to protect the smaller chord) to 15 amps.

[Wowbagger]

The bad thing about relying upon the breaker in the rig to protect the cord is that if the fault exists between the rig and the pedestal, the breaker in the rig won't do a damn thing. e.g., if somebody runs over the cord and damages it, causing it to short, the breaker in the rig will see zero current, and the only limit will be the 30A breaker in the ped.
That said - in my experience most parks that have 30A also have a 15/20A outlet with a 15 or 20A breaker, so if you plug into that outlet you are protected.

[N147JK]

Originally Posted by Wowbagger

The bad thing about relying upon the breaker in the rig to protect the cord is that if the fault exists between the rig and the pedestal, the breaker in the rig won't do a damn thing. e.g., if somebody runs over the cord and damages it, causing it to short, the breaker in the rig will see zero current, and the only limit will be the 30A breaker in the ped.
That said - in my experience most parks that have 30A also have a 15/20A outlet with a 15 or 20A breaker, so if you plug into that outlet you are protected.

Good thought, but in a case like that, the cord isn't being protected from overload because it has been physically damaged - from a circuit protection standpoint, the cord is no longer the focus of protection. If there is physical damage to the cord that causes a short circuit, the pad breaker will trip instantly, regardless of the size or type of cord plugged in.

Yes most places have both 15 and 30 amp service. I switched the breaker to 15 amps for design safety, just in case I end up somewhere that only has 30+ amp service available.

[Scalf77]

To be clear, were not saying changing the 30 amp main to a 15 amp main solves the particular issue that the OP was asking about? He just needs a better extension cord.

In fact changing the main to a 15 in his van would not even guarantee that he didn't pull more than 15 amps. His inverter/charger has an internal 30 amp breaker, changing the main to a 15 would limit the output or passthru to 15, but would not take into account the charger current, so you could still pull 15 + charger AC amps. So while it may limit the input on some rigs, that would not be the case here.

-greg

[1der]

On this trip I forgot to bring our 30amp shore power cord. I did bring the pigtail that adapts our 30 amp van mounted male receptacle to 15/20A male plus a 14ga extension cord. So, I at least we have 15a shore power.

But, I have missed the 30A cord at times. A small electric space heater, electric water heater, and microwave cannot all run at the same time. That does not even include the battery charger requirements and other electrical demands.

Interestingly, at one point a week ago, while on a 15A breaker shore connection, enough load was present to trip the pedestal breaker. The inverter immediately transferred over to handle the loads but in so doing it tripped the BMS on the Lith bank because the loads were still present and exceeded the discharge limitation. Now, the lithium batteries were in DMOS protect mode. Interestingly, after shutting down loads and resetting the pedestal breaker the inverter/charger would not come back on since the batteries were in shutdown. Bit of a catch 22. I had to start the engine and supply the Lith batteries with a charger to clear the BMS protection. Maybe there is a timer in the BMS that would have allowed the batteries to unprotect.

For our use, the 30amp input is a keeper.

[N147JK]

Originally Posted by Scalf77

To be clear, were not saying changing the 30 amp main to a 15 amp main solves the particular issue that the OP was asking about

Yes that's true - my post was not really addressing the OP's original concern. Sorry.

[posplayr]

Originally Posted by 1der

Maybe there is a timer in the BMS that would have allowed the batteries to unprotect.

For our use, the 30amp input is a keeper.

This may be for a much simpler approach, (in my analysis) it is least troublesome to simply use the AC shore power to charge the battery bank. If you have a generator then use a transfer switch for that to change batteries.

Alternatively, if you plan to be on shore power/generator a lot, for these high-load devices just put in a dedicated shore power 120V outlet (GFI).