Hi Anne,
And my are comments inline...
> > Subject: Re: [A/S] 12v outlets
> >
> > Are you talking about the cabinet design, Rick? It's a simple wooden
> > cabinet console with shelf storage under a flat surface area. There are
> > center upright supports and side walls that can hold outlets. This is
> > for a space that replaces the front gaucho on a '99 Safari 27' and the
> > inverter is at the front center underneath the fuse box which is on the
> > wall at the rear of what is now a cabinet. I can take a picture of
> > what's built so far and post it. The carpenter's brother is a licensed
> > electrician but I don't know how much 12v experience he's had.
I understand. 12 volt wiring and requirements are a different ballpark from
ordinary residential or industrial AC wiring. But he should be able to handle
the job if you make sure he is aware of what he needs to look at as he does
the installation.
> >
> > What I am curious about is that these freezers are marketed for extended
> > use on boats and RV's and come in several different brands. I'm hearing
> > you say they are all too beefy for the existing connectors and wiring?
> > Nobody plugs in a freezer for just a few minutes!
Yes, exactly right. Most folks are either using the Anderson Powerpole
connectors, or using some odd and almost never seen AC plug and jack combo for
the 12 volt high current connections. I usually don't recommend last thing and
this because AC receptacle design, i.e. the placement of the pins etc. means
something. Such as the voltage and current rating of the circuit. This is why
a 20 amp receptacle has a vertical and horizontal jack on one side and a
vertical on the other. Other connectors for various current and voltage
ratings are each also designed with unique pins. You don't want anyone making
a mistake as to what type of power is on the jack.
The Powerpole connectors are available in nice wall mount flush receptacles and
even weatherproof ones too, so they're the best to use. You need an Anderson
crimper for the install of the plug and receptacle, and thin makes sure the
wiring gets a good solid connection to the copper and a good strain relief.
They are easy for an electrician to install. I'd recommend them.
I cut off the lighter plugs from the cord ends and put a powerpole on the
cable end. You can have a pigtail made of the cut off end by adding a Powerpole
receptacle, so that you can plug the pigtail on the Powerpole attached to the
freezer and get adapted to a lighter jack for emergencies. If you standardize
on a Powerpole current size connector, this will work on any device you want
to adapt to use a lighter jack.
>
> There are two open 20amp circuits on the coach circuit breaker.
I take it these are 12 volt breakers?
>
> > Also, the freezer power cord/ plug is very secure---believe me I tested
> > it this fall! However I pulled it out by stepping on the cable more
> > than once, which is why it will be much safer in it's own little
> > ventilated space under the shelves.
Trust me, vibration and fatigue will get the spring contacts weakened in the
plug and jack and the heat will do the rest eventually. These are not designed
for continuous use.
> > What would you recommend? If I start cutting off plugs and wiring on new
> > ones, I'll void the warranty and maybe cause other problems. I can't
> > imagine they sell so many of these and don't put on substantial
> > connectors. But I'm open to horror stories if you have them. I'll go
> > try to take a few pictures and upload them if I can get my camera phone
> > to work.
Changing the plug should not void the warranty. This is not a change in any
way to the device except to guarantee that it receives the designed for
voltage and proper current can be supplied to it. Is the cord removable or
replaceable? How is it attached to the freezer?
They sell them because of what folks can immediately plug them into. That does
not make it a good and proper design. And no way is a lighter jack a good 20
amp design.
As to wiring, it's all about voltage drop at the rated current. As I mentioned
if you calculate this, you have to double the wire length because you have to
get back to the inverter, i.e. the positive and negative wire. So the total
wire length is both of them added together. 20 feet from the inverter you have
40 feet of wire.
On a residential AC circuit you can tolerate a few volts of drop due to wire
resistance at the circuit's rated current. You can't tolerate this same drop
at 12 volts as it is a much greater percentage. So the wiring has to be of
lower resistance than traditional residential electrical tables would allow.
Otherwise you are going to see the 12 volts drop to 10 or less under load and
nothing is going to work right. Even a 1 volt drop is way too much.
Fortunately the wire runs are short and the wire sizes are available to do the
job. It just has to be designed in at install. And as I mentioned, the proper
design of stranding, jacket material, and grommeting at bulkheads.
Anyway, just some food for thought...
Rick Kunath
WBCCI #3060
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