I’ll take this one step further and suggest using quality connectors that are specifically labeled as being marine grade.  These would have tinned copper tubing.  I prefer connectors that have heat shrink with adhesive.

And, of course you should be using these with marine grade wire (also tinned copper). 

The headaches you save may be your own.

Peter Nyberg
Coventry, CT
s/v Silverheels (1988/2016)

> On Feb 1, 2021, at 2:51 PM, PBR <pbryanriley at gmail.com> wrote:
> 
> I thought I would drop a note of caution about using harbor  freight
> materials.  I have had a couple of electrical failures of butt joints using
> their connectors.
> 
> When I lived in Denver I drove past a HF store everyday so I picked up a
> lot of cheap stuff there.
> 
> 1) After wiring a new hitch wire harness to my utility trailer using HF but
> joint connectors I wrapped the joints with electrical tape to seal it.
> About a year later the lights weren't working properly and I narrowed the
> failure down to an open circuit in that area under my tape.  Upon removal
> of the tape the wires were just falling off, breaking at 90 angle to then
> ends of  the connector body.  Visible was a lot of corrosion white and
> green material.  I don't think there was any significant water intrusion
> and it's pretty dry in Denver.  I chalked it up to some sort of galvanic
> corrosion between the seemingly aluminum connectors and the copper.
> 
> 2) Meanwhile I had used the HF stuff in other areas too.  LIke my R22 bilge
> pump.  I recently returned to check on my Rhodes after about a 2 month
> absence to find that storms in Kitty Hawk had shredded part of my tarp,
> clogged the drains with tree parts of all nature, and filled the laz with
> water which found its way into the bilge.  Water up to the floor boards -
> why wasn't my automatic bilge pump working?  Traced it to a butt connector
> down at the pump being basically open circuit.  This time I had
> waterproofed the joints with liquid electrical tape or something like it
> and all that was good.  On the outside everything looked water tight and
> this joint was in an area where it never saw stress or chafing.  After
> cutting into it, I again found white and green signs of corrosion.
> 
> Lesson learned.
> 1) don't buy harbor freight (but the only non-chinese made connectors I
> have found are Taiwanese, please advise if you have a north american source)
> 2) I will make sure any butt joints have full copper to copper contact in
> the middle (but that may not help much).