Electrical wiring A/C - 2-prong plug
 

I purchased a rectifier that will provide 24V DC to our Refrig unit when at
dock ( It has an internal switch that disconnects the battery connection
automatically when on A/C power)

This unit came with a two blade plug on the A/C inlet. In other words, no
ground connection. The two blade plug has, as usual, one blade larger than
the other.

I could install a new outlet and plug the unit in, or I could connect it
directly to the A/C panel.

Question: How do I determine which wire (plug blade) goes where when
connecting into the shore power system? Or does it matter?

GBM

Electrical wiring A/C - 2-prong plug
 

It really shouldn't matter - the wires will essentially go straight to a
transformer in the rectifier box, perhaps through a fuse and/or a switch.
The secondary side of the transformer will have some diodes to "rectify" the
AC into DC. Part of their function ensures that the output polarity is
correct. There will usually be some capacitors there to smooth out the
output voltage, and maybe a regulator, if your fridge needs a narrow voltage
range (like a computer does...).

But, if you want to be correct, the long blade goes to the "neutral" side of
the mains, and the short blade goes to the "hot" side, per NEMA guidelines.

It would be very advisable to install anything directly connected to the AC
panel on a protected circuit, meaning on the downside of an existing or new
breaker. Don't just wire to the main distribution busses - if you were to
get a short in the rectifier unit, or in the cable, you would likely have no
overcurrent protection and you'd probably get a fire.

Good luck.
Dennis

"GBM" wrote in message
...
I purchased a rectifier that will provide 24V DC to our Refrig unit when at
dock ( It has an internal switch that disconnects the battery connection
automatically when on A/C power)

This unit came with a two blade plug on the A/C inlet. In other words, no
ground connection. The two blade plug has, as usual, one blade larger
than
the other.

I could install a new outlet and plug the unit in, or I could connect it
directly to the A/C panel.

Question: How do I determine which wire (plug blade) goes where when
connecting into the shore power system? Or does it matter?

GBM

Electrical wiring A/C - 2-prong plug
 

Thanks Dennis - I do plan on installing a new breaker on my A/C panel. I may
just cut the plug off and splice onto a new cable. I will try to ensure
short blade goes to Hot side.

GBM

"Dennis Lee" wrote in message
...
It really shouldn't matter - the wires will essentially go straight to a
transformer in the rectifier box, perhaps through a fuse and/or a switch.
The secondary side of the transformer will have some diodes to "rectify"
the
AC into DC. Part of their function ensures that the output polarity is
correct. There will usually be some capacitors there to smooth out the
output voltage, and maybe a regulator, if your fridge needs a narrow
voltage
range (like a computer does...).

But, if you want to be correct, the long blade goes to the "neutral" side
of
the mains, and the short blade goes to the "hot" side, per NEMA
guidelines.

It would be very advisable to install anything directly connected to the
AC
panel on a protected circuit, meaning on the downside of an existing or
new
breaker. Don't just wire to the main distribution busses - if you were to
get a short in the rectifier unit, or in the cable, you would likely have
no
overcurrent protection and you'd probably get a fire.

Good luck.
Dennis

"GBM" wrote in message
...
I purchased a rectifier that will provide 24V DC to our Refrig unit when
at
dock ( It has an internal switch that disconnects the battery connection
automatically when on A/C power)

This unit came with a two blade plug on the A/C inlet. In other words,
no
ground connection. The two blade plug has, as usual, one blade larger
than
the other.

I could install a new outlet and plug the unit in, or I could connect it
directly to the A/C panel.

Question: How do I determine which wire (plug blade) goes where when
connecting into the shore power system? Or does it matter?

GBM

Electrical wiring A/C - 2-prong plug
 

"GBM" wrote in news:MK8eg.39785$Hk1.12558
@read1.cgocable.net:

I may
just cut the plug off and splice onto a new cable.

Why not get the matching socket for the plug and mount it near the fridge,
making it possible to easily extract the fridge for repair, replacement or
just cleaning behind it, someday.

Any kind of inline splicing usually causes problems down the road from
coming loose to corrosion and certainly makes removing the fridge a pain in
the.....well, you get the idea. Install the outlet for the plug, ok?

Thanks!

The Reefer Guys.

Electrical wiring A/C - 2-prong plug
 

I will install an outlet, but this won't help me remove or clean behind the
"fridge"! The "fridge" is a Waeco evaporator/condenser unit that is built
into the boats icebox ;)

The item I am installing, is a small Mobitronics rectifier that will provide
24V power to the "fridge" when at dock . It automatically switches out the
12v battery DC when activated. Waeco recommend this so as to avoid any
voltage spikes that the on-board charger may cause.

Probably not essential with our Truepower charger, but the eBay price was
right and it provides a neat way of monitoring the "fridge" power usage
(Using a Kill A Watt). This was suggested by someone earlier when I asked
about ways of checking power usage with different amounts of additional
(temporary) icebox insulation.

GBM

"Larry" wrote

Why not get the matching socket for the plug and mount it near the fridge,
making it possible to easily extract the fridge for repair, replacement or
just cleaning behind it, someday.

Any kind of inline splicing usually causes problems down the road from
coming loose to corrosion and certainly makes removing the fridge a pain
in
the.....well, you get the idea. Install the outlet for the plug, ok?

Thanks!

The Reefer Guys.

Electrical wiring A/C - 2-prong plug
 

"GBM" wrote in news:u6Ceg.76030$fd.34300
@read2.cgocable.net:

Waeco recommend this so as to avoid any
voltage spikes that the on-board charger may cause.



Hmm...Interesting. The only way I know of it making a "voltage spike" is
if it is connected to a battery with an open cell. Batteries absorb the
spikes, normally. It's how they charge...(c;

Electrical wiring A/C - 2-prong plug
 

"Larry" wrote

Hmm...Interesting. The only way I know of it making a "voltage spike" is
if it is connected to a battery with an open cell. Batteries absorb the
spikes, normally. It's how they charge...(c;


I think they were talking about higher than normal charger output voltages
in 15+v range that some chargers may put out under certain conditions.

Regarding spikes - Don't we get a "spike" when we turn on the charger?
Instead of say 11.5v, we suddenly have 14.5 or whatever. Anyway, that's
what my voltmeter tells me!

GBM

Electrical wiring A/C - 2-prong plug
 

"Larry" wrote

I think they were talking about higher than normal charger output
voltages in 15+v range that some chargers may put out under certain
conditions.

The charger output into an open circuit is quite high. But, the battery,
itself, will not allow the charger to come anywhere near this voltage
level.

I would have thought that by passing a 10 Amp current through a battery, the
overall resistance of the battery would result in a voltage increase across
the terminals. I am sure that when I hook a low car battery up to my
el-cheapo Sears charger, I get an increase in the standing voltage - Is this
not normal?


To say the charger puts out 15+VDC across a battery only tells me the
battery is overcharged, where battery voltage rises rapidly about 1.260
specific gravity as its electrolyte is converted into hydrogen gas.


Not sure exactly what Waeco are worried about. I was going to connect the
refrig unit only to DC, but the rectifier was available so I decided to
follow the manufacturer's recommendations for once :). It could be that they
were concerned about chargers that can go into equalization mode - Don't
they then put out over 15V?

In any event, I kind of like the idea of bypassing the batteries when using
the refrig at dock. The batteries can be brought up to full charge quicker
without the refrig drain.

GBM

Electrical wiring A/C - 2-prong plug
 

If the batteries suddenly spike from 11.5V to 14.5V when connected to the
charger, that is an indication that the batteries are worn out. A battery
that is good takes time to discharge and little longer to charge. There
are a lot of variables, such as the size of batteries vs. size of charger.
Generally batteries should be kept above 12.2V, otherwise they have short
life. Thousands of boats have A/B fridge systems (including mine), all
have battery chargers, they work reliably without add'tl equipment.
Lee Haefele
Nauticat 33 Alesto
"GBM" wrote in message
...

"Larry" wrote

Hmm...Interesting. The only way I know of it making a "voltage spike" is
if it is connected to a battery with an open cell. Batteries absorb the
spikes, normally. It's how they charge...(c;


I think they were talking about higher than normal charger output voltages
in 15+v range that some chargers may put out under certain conditions.

Regarding spikes - Don't we get a "spike" when we turn on the charger?
Instead of say 11.5v, we suddenly have 14.5 or whatever. Anyway, that's
what my voltmeter tells me!

GBM