Appreciate help installing inverter

[CharlieJ]

@ john_manning #30
Your comment is simply not true. Please refrain from giving advice regarding AC systems as the wrong advice, if acted on, can lead to damage or injury.

[Nate24]

Originally Posted by arch007

Installing 700 w inverter

Have some questions

1. How important is it to ground the inverter ?

Ground the inverter case with a DC cable no less than one gauge lower than the necessary cable size for the battery to inverter cables. That is the ABYC requirement. Grounding the inverter is prudent and critical.

Ground to engine block or water via seacock ?

Ground to the engine, or to a negative buss bar. It is essential that it join the overall grounding system of the boat.

2. When installing i plan to attach positive then negative. Is this ok ?


3. There is a 250 amp fuse in the positive battery terminal. This is a common fuse for all connections. Is this too high ?

The fuse protects the cable. It should be sized to handle the current capability of the cable feed. The cable feed should be the highest expected current feed within the system. That is typically the highest estimated echarge acceptance rate of the battery bank.

Thanks in advannce

Hope this helps.

[bcboomer]

Originally Posted by CharlieJ

The case ground is required to be the same size as the DC positive cable or one size smaller under some conditions. And yes, it does go to the same DC negative bus as the DC negative supply but it serves a completely, and important purpose.

It's a short run to the buss bars and the Blue Sea app says AWG10 wire is correct for the DC supply, both positive and negative in my application.
On a stand alone 300 watt inverter would an AWG10 jumper from the case ground to the DC ground on the inverter not serve the same purpose as a separate wire? 2 wires going side by side seems redundant.
Assuming a short from the AC side to the case then the DC positive 40 amp fuse at the buss bar will blow before the AWG10 wire gets hot.
This is a simple inverter so there is no AC source except the inverter.

[ovidiunelu]

Originally Posted by arch007

Installing 700 w inverter

Have some questions

1. How important is it to ground the inverter ?

Ground to engine block or water via seacock ?

2. When installing i plan to attach positive then negative. Is this ok ?

3. There is a 250 amp fuse in the positive battery terminal. This is a common fuse for all connections. Is this too high ?

Thanks in advannce

you will need a switch to keep the shore power and invertor separate and a breaker just for the invertor you will want it off when not in use it drain batteries very fast even not in use

[CharlieJ]

@bcboomer
I have not read the tech manual for this unit but if it is a reputable manufacturer, it will have instructions for connecting the case ground to be in compliance with the NEC. Unfortunately, the NEC does not cover all things electrical on a boat. In the USA, those standards are written by the American Boat and Yacht Council which I summarized upthread.

In the EU, ISO 13297 is the applicable standard concerning inverters and inverter/chargers, it is codified in law, and it requires a separate case ground.

If the manufacture intends on the buyer to install their product on a boat, they will provide instruction IAW the ABYC and the ISO Standards.

So, the manufacturer and three standards writing bodies specify a case ground that is redundant to the B- and you want to debate its applicability. As I tell my clients when we disagree: IYB (It's Your Boat.)

[john manning]

Originally Posted by CharlieJ

@ john_manning #30
Your comment is simply not true. Please refrain from giving advice regarding AC systems as the wrong advice, if acted on, can lead to damage or injury.

Thanks for your opinion. My advice was not entirely mine. I am an engineer not an electrician so before making my comment I spoke to one of the three electricians I employ. The one I spoke to is a Marine Engineer (Electrician) with over 30 years experience on yachts and ships, including over 10 years at sea. He has extensive experience installing and repairing power supply systems. Because I have seen his work and its results for nearly 10 years now, I think I will continue to respect his advice.

[CharlieJ]

@john_manning #36
Not my opinion, but the requirements of the NEC, ABYC and ISO 13297.

[john manning]

Originally Posted by CharlieJ

@john_manning #36
Not my opinion, but the requirements of the NEC, ABYC and ISO 13297.

Charlie J you now have got me interested in the interpretation of standards in other countries. (My business works on foreign vessels in NZ so it is of some significance to me.)

The concept of "above earth" and bonding straps in NZ is based on the idea that mobile power supplies do not have a true earth connection. So mobile homes, boats and small portable generators are wired to their own earth plane which is not grounded in a true sense.

Our interpretation is that a boat does not have an earth ground unless it is connected to shore power main supply. Once that power lead is removed any grounding via seawater is not considered adequate and in mobile home situations the vehicle tyres insulate the power supply from ground. Consequently we have a requirement to prove bonding between all the cases of electrical equipment to create a common plane (earth) which will ensure a fuse or breaker is tripped when a fault occurs. We test for both the continuity and current capacity of the bonding circuit.

I would be interested to know how your systems work and how the earthing standards are interpreted where you live.