battery charger extension cord confusion

[Buddy_Y]

I'm embarrassed asking this question, but... I'm just about to install a ProSport HD 20 plus battery charger in a C&C 30 I'm bringing back from the dead, and I expected to simply create a dedicated 20 amp GFCI for it (off a Blue Seas AC distribution panel) and just plug the thing in. But to my surprise, the installation instructions seem to insist that I add in an extension cord too:

Connect a heavy duty UL approved extension cord to the ProSportHD charger first. After connecting the extension cord to the charger, proceed to plug the extension cord to a nearby GFCI protected (Ground Fault Circuit Interrupt) outlet. Always remove the extension cord from the outlet first when charging is completed, followed by unplugging the charger.

The original text can be found on page 16 of the manual here (item #11). I figured that I had to be misreading it -- that the manual was saying that IF you need an extension cord, then blah blah. But darned if the instructions don't seem to say you must use an extension cord.

Is there a reason for this? Or is it just an badly worded manual?

[Wotname]

After reading the manual I would suggest it is simply badly worded - perhaps because the power cord seems short in the images, they expect most will using an extension cord (??).

There can't be any electrical reason for requiring an extension cord.

[Buddy_Y]

That's what I figured, but I'm such a DIYer dilettante that I tend to second-guess myself. Thanks!

[tkeithlu]

Lots of owner's manuals out there were written by people for whom English is at best a second language, and whose first language uses a completely different grammer.

In this case and others, think your way through it, and trust yourself not to do anything really awful. An extension cord just moves the location of the outlet by extending the wires. The only real considerations are amperage (versus diameter and length of the wires) and condition of the cord. Don't run something that does a lot of work off a long skinny extension cord. For that matter, invest in a few 12 or even 10 gauge industrial extension cords and never have to worry about it.

[Pete7]

Is this to stop someone holding a live extension cord whilst trying to connect it to the battery charger? Assuming they do as they are told, then even if they mess up the wiring at least they won't be holding it when there is a big flash and loud bang. Its not good for business to loose customers.

Pete

[GreenWave]

I don't know any electrician who would tell you that having an extension cord in the circuit is required, or even good in most cases. You need to be able to unplug it and if that can be done with the cord end provided then so be it.

[Redline452]

I think the intent of the instruction is that the connection to the outlet be done last; so if you have an extension cord, plug it into the charger first, then to the outlet. Shouldn't make a big difference, but does move the spark at initial connection, if any, farther from the charger (and battery). Also makes it less likely that an already-live extension outlet be dropped into the water, or bilge.



But if you don't need an extension, then don't - fewer connections and shorter wires are always a good thing.


(speaking personally, though I'm also an electrical engineer)

[waterman46]

This falls into the category of useless instructions that I love to violate whenever I can. Example - the "do not remove" on mattress tags ( I love to rip those off) and another "Do not wheel with lid open" on my garbage and recycling bins ( I open the lid and wheel it whenever its more convenient).

Maybe we need a thread to collect such useless or amusing instructions.

[StuM]

Originally Posted by waterman46

This falls into the category of useless instructions that I love to violate whenever I can. Example - the "do not remove" on mattress tags ( I love to rip those off) and another "Do not wheel with lid open" on my garbage and recycling bins ( I open the lid and wheel it whenever its more convenient).

Maybe we need a thread to collect such useless or amusing instructions.

I disagree.
Although it should begin by explictly stating the implied "If using an extension cord..." the instructions given for using an extension cord are 100% correct, violating them creates electrical hazards and would be extremely foolish.

[Buddy_Y]

Thanks everyone! One of the ironies is that I've paid for the boat and its refit as a staff writer-editor. I found it hard to believe they'd write something so ass-backward; whereas, in contrast, I'm always willing to believe that there's some tech tidbit I don't know about.