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Jeff Cote here from Pacific Yacht Systems I've got a question from a fellow boater and this boater asks Jeff do the cables from the alternator have to be the same length I.E the negative and the shorter the negative and the positive can do they have to be the same length or can they be different lengths good question the reality is most alternators don't even have a negative post the chassis of the engine block is how the negative uh the current on the alternator actually goes probably through one of the negative connections on the chassis block and generally it's not isolated at the start at the alternator so in short yes you can have a positive and a negative wire being different lengths because it's really the sum of those two sides and it could be shorter on one side for whatever reason you could have a shorter negative circuit because maybe the battery bank is really big and the positives on one end of the bank and the negative is at the other end of the bank and the alternator is right there so the positive wire has to go to one side of the boat and the negative goes to the other side and it's quite possible that the negative wire is going to be shorter than the positive wire and that's not an issue of course the aggregate aggregate length this those two are going to be useful to calculating the voltage drop because your circuit is going to have to go through all the red through the batteries and through the negative to go back so yes that would be something you want to take into consideration when you calculate voltage drop but yes the cabling can be of different lengths now a note here it's important to remember there are very few alternators it does exist but many of them do not have an isolated negative return meaning um some of the current coming from the negative posts of the alternator is actually going to go through the chassis and will connect to the engine block negative to get back to your battery it might be desirable to have a alternator that isolates and that current do not go through the engine block and then the alternator itself has a positive and negative post and all the current for that alternator stays on the positive and negative post but it's not something that's all that common and that's why often you see an alternator with only a positive cable and no negative cable and that negative is taking from the chassis which has to have a connection otherwise the starter won't work same thing with a starter you'll notice that starter solenoids only have a positive wire the negative wire doesn't go back to the solenoid it actually goes to the engine chassis so again it's not uncommon to have different length cabling on an alternator circuit so thanks for asking your question and thanks for all of you for tuning in and trying to learn more about Marine electrical thanks for your time and joining us so if you're curious again go on our website and find out more answers and solutions with this sort of setup and thanks for asking and thanks for all of you for listening and tuning in