Galley Switch

dvd · Dec 22, 2011

I'm renovating my all-electric galley and have replaced a Princess stove/oven unit with a combined microwave/convection oven (1000W) and a separate induction cooktop (1250W). The Princess (with one power source) had a selector switch to use either the cooktop or the oven but not both at the same time. I would like to set up the new galley the same way so that a handy switch would allow either the microwave/convection oven or the induction cooktop to be used, but not at the same time. What would be the best kind of switch for this application?

*

Thanks,

dvd

RickB · Dec 22, 2011

It all depends on where in the circuit you want to install the switch. Is it going to be on the unit itself and void your warranty?

You really need to have someone with electrical skills look at the schematic and advize you.

Ah, just reread and saw where they are entirely independent units. In that case a properly rated DPDT switch will do the job nicely.

*

-- Edited by RickB on Thursday 22nd of December 2011 12:53:16 PM

Phil Fill · Dec 22, 2011

Why not use the one that is on the old unit?

dvd · Dec 22, 2011

I have installed a 20A duplex receptacle but separated the two plugs so the cooktop will go to one plug and the microwave to the other. I would like to wire it so that the switch feeds either one or the other plug and the switch is handy to the galley location (i.e., not have to go over to the e-panel).

(The old unit was sold.)

dvd

-- Edited by dvd on Thursday 22nd of December 2011 12:57:23 PM

RickB · Dec 22, 2011

dvd wrote:I have installed a 20A duplex receptacle but separated the two plugs so the cooktop will go to one plug and the microwave to the other.*

Supply the power to those plugs through a properly rated DPDT switch. In one position it supplies one outlet, in the other it supplies the other.

*

Or, if you are just shopping for answers, use a Krytron or a pulse neutron tube.

dvd · Dec 22, 2011

Thanks, just picked up a 20A DPDT at Graingers -- they were out of pulse neutron tubes.

dvd

rwidman · Dec 27, 2011

A single pole, double throw switch will be fine. You don't have to switch the neutral.

RickB · Dec 27, 2011

rwidman wrote:
*You don't have to switch the neutral.

Good marine electrical practice demands switching both conductors. It is a safety issue for AC circuits and is the only way to assure isolation of a load.

If one is going to play marine electrician, one should take a professional approach.

rwidman · Dec 27, 2011

RickB wrote:rwidman wrote:
*You don't have to switch the neutral.

Good marine electrical practice demands switching both conductors. It is a safety issue for AC circuits and is the only way to assure isolation of a load.

Not really.* Look inside your electrical panel.* All the branch circuits use single pole breakers.* They switch the hot wire only.

*

-- Edited by rwidman on Tuesday 27th of December 2011 05:50:54 PM

RickB · Dec 27, 2011

Look between your deck layers, it is probably rotting plywood. Just because recreational boat builders do certain things doesn't mean they are doing it right or even using best practices.

Marine AC switches should break both conductors. In this case where the installer has the option to do it cheap or do it safely and adhere to best practice, I suggest best practice in favor of saving a foot of wire and $2. This particularly applies to a galley fixture.

I guess we have different standards.

skipperdude · Dec 29, 2011

I read the entire thread twice and will have to side with Rick on this one.

Best practice vs It will work fine.

You can always do what will work but sometimes there is a better way. Especially when working with something that could be hazardous as in a galley where a fire could occure.

SD

*

*

-- Edited by skipperdude on Thursday 29th of December 2011 02:29:38 PM

dvd · Dec 29, 2011

All very entertaining, but while the keyboards clacked away I installed my 20A DPDT switch and it's working great!

Thanks,
dvd

-- Edited by dvd on Thursday 29th of December 2011 03:32:06 PM

rwidman · Dec 29, 2011

skipperdude wrote:
I read the entire thread twice and will have to side with Rick on this one.

Best practice vs It will work fine.

You can always do what will work but sometimes there is a better way. Especially when working with something that could be hazardous as in a galley where a fire could occure.

SD

*-- Edited by skipperdude on Thursday 29th of December 2011 02:29:38 PM

"Best practice"?* Switch it the way everything else on a boat is switched.**Switch the hot wire.* There is absolutely no reason to switch both wires.* If there was, it would be an ABYC requirement.

You can switch both wires, you can even switch the bonding conductor but why?* All you will accomplish is to make things more difficult and confuse anyopne who ever works on your electrical system in the future.

Being in the galley makes absolutely no difference.* Take that stove or microwave apart and you will find that the manufacturer only switches the hot wire.

This is electricity 101.

FlyWright · Dec 29, 2011

*

dvd wrote:
All very entertaining, but while the keyboards clacked away I installed my 20A DPDT switch and it's working great!

Thanks,
dvd

-- Edited by dvd on Thursday 29th of December 2011 03:32:06 PM

*

Well that's just GREAT! And to think I was just pulling up a chair with a full bowl of popcorn! I guess the show is over. Now we can all go about our own business. (whistling innocently...)

-- Edited by FlyWright on Thursday 29th of December 2011 07:27:17 PM

FF · Dec 30, 2011

"I would like to set up the new galley the same way so that a handy switch would allow either the microwave/convection oven or the induction cook top to be used, but not at the same time. What would be the best kind of switch for this application?"

Of course a fellow interested in conserving his energy might select a load shedding switch , so one item could be on , but would be automatically shut off when the second item is selected.

Graingers , about $60, for the automatic everything folks.

dvd · Dec 30, 2011

FF wrote:

Of course a fellow interested in conserving his energy might select a load shedding switch , so one item could be on , but would be automatically shut off when the second item is selected.

*Ummm. Isn't that what an On-On DPDT switch does? (for $11)

rwidman · Dec 30, 2011

First, unless there's an electrical problem or limitation that won't allow the oven and cooktop to be used at the same time, all this switching will accomplish is to make it more difficult to cook meals. I (and my wife) often use the burners and microwave or oven at the same time when preparing a meal.

Second, as I previously posted, there's absolutely no need to switch the neutral if a switch to select one appliance or the other is desired.* A simple SPST switch will do the job as long as it's rated for the current.

Third, I'll make a guess that this "automatic load shedding switch" only switches the hot conductor. It also confuses the cook and makes the boat more complicated and prone to trouble.

Let's remember the "KISS" principle here: Keep It Simple, Stupid.

-- Edited by rwidman on Friday 30th of December 2011 07:07:28 AM

-- Edited by rwidman on Friday 30th of December 2011 07:08:43 AM

rwidman · Dec 30, 2011

RickB wrote:
Good marine electrical practice demands switching both conductors. It is a safety issue for AC circuits and is the only way to assure isolation of a load.

Not so. You can assure "isolation of a load" by unplugging it.

*

skipperdude · Dec 30, 2011

rwidman wrote:
*

.* All the branch circuits use single pole breakers.* They switch the hot wire only.

*

What is ment by branch circuits.

I thought he was setting things up with a seperate circuit for the application? He seems to indicate not wanting to have to go to the electrical pannel to change circuits.

Would there be any difference if he was running things off an inverter or the shore power?

SD

rwidman · Dec 30, 2011

skipperdude wrote:rwidman wrote:
*

.* All the branch circuits use single pole breakers.* They switch the hot wire only.

*

What is ment by branch circuits.

I thought he was setting things up with a seperate circuit for the application? He seems to indicate not wanting to have to go to the electrical pannel to change circuits.

Would there be any difference if he was running things off an inverter or the shore power?

SD

Just like in your home, on a boat there is a circuit supplying power to the main circuit breaker (or fuse in the "old days") panel.* The circuits leaving that panel are "branch circuits".* They are each protected by a circuit breaker (or fuse) that opens the "hot" conductor if there is a short circuit or overload.

If you have a circuit from the main panel that supplies power to a sub panel, the circuits leaving the sub panel would also be considered "branch circuits".

The same terminology would apply to DC circuits.

An inverter (or genset) is no different, it is merely a self contained power source.

And just so there's no misunderstanding. there can be more than one circuit supplying power to the main circuit breaker panel (shore power, genset, or inverer), but only one can be used at a given time.

*

skipperdude · Dec 30, 2011

rwidman wrote:
*

Just like in your home, on a boat there is a circuit supplying power to the main circuit breaker (or fuse in the "old days") panel.* The circuits leaving that panel are "branch circuits".* They are each protected by a circuit breaker (or fuse) that opens the "hot" conductor if there is a short circuit or overload.

If you have a circuit from the main panel that supplies power to a sub panel, the circuits leaving the sub panel would also be considered "branch circuits".

The same terminology would apply to DC circuits.

An inverter (or genset) is no different, it is merely a self contained power source.

And just so there's no misunderstanding. there can be more than one circuit supplying power to the main circuit breaker panel (shore power, genset, or inverer), but only one can be used at a given time.

*

*It sounded to me he was running the cook top and oven off a seperate circuit.

If it was a seperate circuit would* RickB response have any validity?

Just trying to get an understanding as to the reason he would reply to the method of switching that he did. I am not an electrician or a marine electrician and have never taken any electrical theory classes 101 or above.

Rick seems to have made his living doing this sort of thing for many years.

I would tend to think he knows of which he speaks.

Is the current diatribe a matter of opinion where as one can agree to disagree? Or variations on theory or school of thought concerning electrical theory.

SD**

rwidman · Dec 30, 2011

skipperdude wrote:rwidman wrote:
*

Just like in your home, on a boat there is a circuit supplying power to the main circuit breaker (or fuse in the "old days") panel.* The circuits leaving that panel are "branch circuits".* They are each protected by a circuit breaker (or fuse) that opens the "hot" conductor if there is a short circuit or overload.

If you have a circuit from the main panel that supplies power to a sub panel, the circuits leaving the sub panel would also be considered "branch circuits".

The same terminology would apply to DC circuits.

An inverter (or genset) is no different, it is merely a self contained power source.

And just so there's no misunderstanding. there can be more than one circuit supplying power to the main circuit breaker panel (shore power, genset, or inverer), but only one can be used at a given time.

*

*It sounded to me he was running the cook top and oven off a seperate circuit.

If it was a seperate circuit would* RickB response have any validity?

Just trying to get an understanding as to the reason he would reply to the method of switching that he did. I am not an electrician or a marine electrician and have never taken any electrical theory classes 101 or above.

Rick seems to have made his living doing this sort of thing for many years.

I would tend to think he knows of which he speaks.

Is the current diatribe a matter of opinion where as one can agree to disagree? Or variations on theory or school of thought concerning electrical theory.

SD**

We certainly do disagree.* I think he is enjoying it more than I am.

There's no harm in disconnecting or switching both the hot and neutral conductors but there's nothing to be gained from it either.* Standard practice is to switch the hot conductor only.** Being on a seperate circuit (a stove would normally be on a seperate circuit) makes no difference.

*

bobofthenorth · Dec 30, 2011

skipperdude wrote:
*

Rick seems to have made his living doing this sort of thing for many years.

I would tend to think he knows of which he speaks.

Is the current diatribe a matter of opinion where as one can agree to disagree? Or variations on theory or school of thought concerning electrical theory.

SD**

Its entirely possible to do something for many years and still be doing it wrong after all those years.* Its also possible to do something for hire and overdo it so that you can overbill accordingly.* I'm not saying either of those is the case here but ABYC doesn't think both conductors need to be switched in this circumstance & that's good enough for me.

RickB · Dec 31, 2011

There is a hot lead and a neutral supplying two outlets in the galley. Due to the nature of the loads, use of those outlets is mutually exclusive, only one will be used at a time.

Because the loads are in a galley (a notoriously risky environment for electrical usage) and the neutral may or may not be grounded at some point and the equipment housings may or may not be connected to a safety ground it is easlly possible that an electrical fault in one device could create a ground fault that will create a shock potential to anyone touching the housings of both items at the same time. If a ground fault circuit interrupter is not fitted, this possibility is even more likely.

By using a DPDT switch to direct power and neutral from one outlet to the other and at the same time, completely isolate the other device electrically, the risk of electric shock from that type of fault is completely eliminated.

I don't sell parts, I don't install parts, and I don't make up invoices for parts. I don't make or lose money by people building to NASA standards or to shadetree standards. I don't live in the past and I keep very up to date on the latest "best practices" and incident and accident analyses. I know all the shortcuts and which ones are worth taking and which ones are just lazy or cheap ... I didn't say inexpensive, I said cheap. I go for quality, dependability, safety, and economy, most of the time those are not mutually exclusive but are indeed interedependent.

I know how I do my own work on my own boats and that is generally the way that I suggest to readers on this forum. That "way" may or may not be the same "way" as I suggest to my clients and the reasons are many and from the reception I get here from some, beyond the comprehension of those folks.

To tell the truth, it is New Years Eve, I am on a very nice large yacht in the lagoon at Bora Bora, and I have more interesting and pleasant things to think about than what a few people think about why I suggest one thing over another.

Happy New Year to all.

Tom.B · Dec 31, 2011

Ya' know... I was totally onboard with ya' until the last sentence. Now I am jealous and only wish my new year was as cool as yours, however, I'm pretty sure it won't be. So, are you the first to celebrate or the last?

rwidman · Jan 2, 2012

Obviously, the only truly safe way to do this is to install only one outlet and plug whichever appliance you wish to use into the outlet. Whan using neither, unplug them both. Then, and only then, will you be safe.

koliver · Jan 2, 2012

You guys have me wishing I was on my boat, just so I could unnplug my microwave in order to plug in my diesel stove, all the while swinging at anchor in princess cove, Wallace island (below).

Bora Bora, eat your heart out.*

*

Happy New Year to all!

sunchaser · Jan 2, 2012

Ron

My convection microwave is plugged into the wall (can't see where) and my electric stove top is hardwired into*a separate breaker. I guess this isn't the right way according to your one plug "truly safe way" statement. I will call Art DeFever forthwith and tell him he screwed it up on hull #168.

rwidman · Jan 2, 2012

sunchaser wrote:
Ron

My convection microwave is plugged into the wall (can't see where) and my electric stove top is hardwired into*a separate breaker. I guess this isn't the right way according to your one plug "truly safe way" statement. I will call Art DeFever forthwith and tell him he screwed it up on hull #168.

Read this:

http://en.wikipedia.org/wiki/Sarcasm

*

*

rwidman · Jan 2, 2012

sunchaser wrote:
Ron

My convection microwave is plugged into the wall (can't see where) and my electric stove top is hardwired into*a separate breaker. I guess this isn't the right way according to your one plug "truly safe way" statement. I will call Art DeFever forthwith and tell him he screwed it up on hull #168.

Just so there's no confusion, your setup is perfectly safe and normal.* Notice that Mr. DeFever saw no need to switch both the hot and neutral wires when he designed your boat.

*

Galley Switch

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