Reply
 
Thread Tools Display Modes
 
Old 10-29-2014, 09:41 AM   #21
Senior Member
 
obthomas's Avatar
 
City: Seabrook Texas
Country: USA
Vessel Name: TheVenture
Vessel Model: 1985 Bestway Labelle Sundeck 40ft
Join Date: May 2013
Posts: 462
You guys with U.S. shore power using split phase power to get two feeds of 120 be careful with adding a 220 volt heating element. If you do you are connecting those phases that were separate and safe and creating a dangerous situation with breakers and hot plugs etc. 220 on these systems is not a good idea.
__________________
Advertisement

obthomas is offline   Reply With Quote
Old 10-29-2014, 10:15 AM   #22
JEP
Member
 
City: Madison
Country: USA
Vessel Model: 34' mainship motor yacht
Join Date: Oct 2014
Posts: 24
On demand water heater

You might want to look at a rheem prestige series 95 8.5 gal flow or a RTE 3 low flow which is a single fixture heater. All or 110v and the later is very water conscious. I have used both in home and office applications. They worked fine. As far as the scaling problem, all of them regardless of which one requires a yearly descaling. Very simple process which I do my on with vinegar and water. Takes about 30 minutes.
I rented a motor home a few weeks ago and it had a on demand water heater and it was awsome for a long hot shower. Maybe check the Rv centers. Hope this helps.
JEP.
__________________

JEP is offline   Reply With Quote
Old 10-29-2014, 12:11 PM   #23
Guru
 
psneeld's Avatar
 
City: Avalon, NJ
Country: USA
Vessel Name: Freedom
Vessel Model: Albin 40
Join Date: Oct 2011
Posts: 15,937
Quote:
Originally Posted by obthomas View Post
You guys with U.S. shore power using split phase power to get two feeds of 120 be careful with adding a 220 volt heating element. If you do you are connecting those phases that were separate and safe and creating a dangerous situation with breakers and hot plugs etc. 220 on these systems is not a good idea.
can't you just add a mini-220 sub-panel?...and even then....doesn't it wind up being the same thing?
psneeld is online now   Reply With Quote
Old 10-29-2014, 01:41 PM   #24
Senior Member
 
obthomas's Avatar
 
City: Seabrook Texas
Country: USA
Vessel Name: TheVenture
Vessel Model: 1985 Bestway Labelle Sundeck 40ft
Join Date: May 2013
Posts: 462
The problem is....once you are onboard the split phases are protected with 2 pole breakers that protect one phase and a neutral. These 50 amp two pole breakers are not linked giving you two independent pools of power. Now you bridge then with a heating element and you inadvertently re-connect the two phases. You can predict that if for some reason a short or maybe even maintenance, one of the pools of power is switched off and not being in lockstep with the other , you have left a very dangerous cross connect and the power you thought was off is still there coming across the 220 heating element. In addition if you have any boatside plugs that can be touched they are possibly live also. In summary it is a very good arrangement to use split phase power to provide two separate pools of power, it is not safe to then link them together using 220 volt loads.
obthomas is offline   Reply With Quote
Old 10-29-2014, 06:14 PM   #25
Guru
 
psneeld's Avatar
 
City: Avalon, NJ
Country: USA
Vessel Name: Freedom
Vessel Model: Albin 40
Join Date: Oct 2011
Posts: 15,937
Isn't it that way in a house though .....if you went back to a sub panel with a double pole hot breaker??
psneeld is online now   Reply With Quote
Old 10-29-2014, 07:28 PM   #26
Guru
 
BobH's Avatar
 
City: Montgomery, TX
Country: USA
Vessel Model: None, but looking
Join Date: Feb 2012
Posts: 779
Every house we have ever owned had a 220 VAC service split into two 110 VAC services. Appliances that were/are 220 VAC have a ganged two pole breaker. I have used the same arrangement on our last boat to power a 220 VAC watermaker. Obviously, if you have a 220 VAC appliance it needs to be protected with a two pole ganged breaker. It's not rocket science.

Bob
BobH is offline   Reply With Quote
Old 10-29-2014, 09:35 PM   #27
Guru
 
Capt.Bill11's Avatar
 
City: Sarasota/Ft. Lauderdale
Country: USA
Join Date: Apr 2014
Posts: 5,422
Quote:
Originally Posted by obthomas View Post
In summary it is a very good arrangement to use split phase power to provide two separate pools of power, it is not safe to then link them together using 220 volt loads.
So how do you explain all the boats that have one 50a or one 100a 125v/250v cord yet run both 125v and 250v equipment off that single cord with out any issues?
Capt.Bill11 is offline   Reply With Quote
Old 10-30-2014, 08:39 AM   #28
Senior Member
 
obthomas's Avatar
 
City: Seabrook Texas
Country: USA
Vessel Name: TheVenture
Vessel Model: 1985 Bestway Labelle Sundeck 40ft
Join Date: May 2013
Posts: 462
On a boat including mine the incoming phases are very often individually protected by a breaker that switches one hot and its neutral. A house on the other hand has both phases protected by a two pole breaker that is linked. When there is a fault in the house both phases are switched off every time. In a boat with the circuit breakers being independent and the second pole on each breaker switching the neutral it is different than a house. When you add 220 appliances to a boat it is dangerous if you do not re-arrange the main breakers to be interlocked like a house. If you can't see this problem I'm sorry but I have given the best explanation I can.

Please note that if your boat is wired like a house then the danger goes away. Most boats like mine are not wired like a house.
obthomas is offline   Reply With Quote
Old 10-30-2014, 09:06 AM   #29
Senior Member
 
obthomas's Avatar
 
City: Seabrook Texas
Country: USA
Vessel Name: TheVenture
Vessel Model: 1985 Bestway Labelle Sundeck 40ft
Join Date: May 2013
Posts: 462
Quote:
Originally Posted by Capt.Bill11 View Post
So how do you explain all the boats that have one 50a or one 100a 125v/250v cord yet run both 125v and 250v equipment off that single cord with out any issues?

The boats you speak of are wired like a house and have the main incoming phases through the same two pole linked breaker.

I am speaking to adding a 220 appliance to a boat for example that has two 30 amp or 50 amp shore cords. You can do it same as the boats you speak of but it is not safe.
obthomas is offline   Reply With Quote
Old 10-30-2014, 01:27 PM   #30
FF
Guru
 
FF's Avatar
 
Join Date: Oct 2007
Posts: 16,537
Looked at it for our home and instant electric would have required a complete require 60A per LEG!!!


Our solution was a very high quality GRP inside and out tank, with great insulation that only looses 5deg C in 24 hours.

A super insulated tank might work if there is no dishwasher and washing machine.

Use the waste heat from your refrigeration as heat source. OTS
FF is offline   Reply With Quote
Old 10-30-2014, 04:23 PM   #31
Dauntless Award
 
Wxx3's Avatar
 
City: New York, NY
Country: USA
Vessel Name: Dauntless
Vessel Model: Kadey Krogen 42 - 148
Join Date: Jan 2013
Posts: 2,313
Quote:
Originally Posted by psneeld View Post

can't you just add a mini-220 sub-panel?...and even then....doesn't it wind up being the same thing?
That is sorta where I am right now, but even simpler.

I've cut the 120v wires just before they go into the water heater and inserting a male and female plug, make on the heater side.

That way the water heater is totally isolated but still protected through the ground fault of the 220v shore power system.

The cord coming from the transformer ends in a female plug also. That way WH can only be connected to one power source at a time.

I'm using the German plugs, since I have them and I'll remember it's 220!
__________________
M/Y Dauntless, New York
a Kadey Krogen 42 Currently https://share.delorme.com/dauntless
Blog: https://dauntlessatsea.com
Find us: https://share.delorme.com/dauntless
Wxx3 is offline   Reply With Quote
Old 10-30-2014, 04:32 PM   #32
Dauntless Award
 
Wxx3's Avatar
 
City: New York, NY
Country: USA
Vessel Name: Dauntless
Vessel Model: Kadey Krogen 42 - 148
Join Date: Jan 2013
Posts: 2,313
Having the fridge and freezer already on 220v shore power, means that if I am not in the boat using lights and stuff, the solar panels produce enough to keep the batts up, even on rainy days.

Once I get an auto radio, I'll hook it up to the auto pilot and I won't have to worry about a constant lookout, as I won't even be on the boat.

It could be the first Kadey Krogen drone:-)
__________________
M/Y Dauntless, New York
a Kadey Krogen 42 Currently https://share.delorme.com/dauntless
Blog: https://dauntlessatsea.com
Find us: https://share.delorme.com/dauntless
Wxx3 is offline   Reply With Quote
Old 10-30-2014, 04:52 PM   #33
TF Site Team
 
Larry M's Avatar
 
City: JAX, FL
Country: USA
Vessel Name: Hobo
Vessel Model: Krogen 42-120
Join Date: Nov 2008
Posts: 5,751
What did you do for the water heater?
__________________

Larry M is online now   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off





All times are GMT -5. The time now is 11:49 AM.


Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2006 - 2012