Dinette AC Outlet Ampere Rating

Gregory Beach

Gregory Beach

Member
Sep 3, 2020
33
Tacoma, WA
Boat Info
2012 310DA
Kohler 5EKD
Engines
Twin 305 MerCruisers w/ Bravo III Drives
DTS w/ Axius
Hello!

Looking to understand enough about power systems to calculate what type of space heater I could purchase and safely use for the cabin (supervised only, of course). I'm seeking to use the dinette AC outlet on the starboard side.

I can't glean enough from the electrical diagrams to feel confident enough, and am OK either receiving an honest and concise answer, or a pointer in the right direction to learn myself.

Thanks in advance,
Greg
 
Last edited:
Yup - if you want to confirm, just look at the breaker for the system. Or, another way to tell is by looking at the outlet. You know what a 15a outlet looks like because it's the one in your boat. Google for a 20a outlet and you'll see the difference. You can plug a 15a item into a 20a receptacle, but you can't physically plug a 20a item into a 15a receptacle.

If you look around your house, you should see a difference, too. If you look at the outlets around your kitchen counter top, those are typically 20a outlets (unless the wiring is really old and hasn't been updated in a long time).

In a nutshell, if the heater has a "normal" plug (15a), you're good.
 
Mine are also rated at 15A. As a good practice, you should not load a receptacle more than 80% of it's rating for long periods.

So, limit the load to 12A, or about 1300-1400watts. Also keep in mind that most dock electrical systems are poor, and you're probably not getting 120 V to your boat. If the voltage is too low, some of your devices may operate out of spec, so keep an eye on that.
 
My direct experience - you cannot run a 1500W space heater on "high" on a Sea Ray circuit for more than a few minutes before the breaker will pop. If you end up buying a 1500W heater make sure it has multiple output settings.

For me low seems to work perfectly. I imagine that's around 1000W +/- on the Honeywell unit I run during the shoulder seasons.
 
Stee6043 said:
My direct experience - you cannot run a 1500W space heater on "high" on a Sea Ray circuit for more than a few minutes before the breaker will pop. If you end up buying a 1500W heater make sure it has multiple output settings.

For me low seems to work perfectly. I imagine that's around 1000W +/- on the Honeywell unit I run during the shoulder seasons.
Click to expand...
Another factor is that GFCI's and breakers tend to pop more often as they age. They, like us, simply get worn out! It's also possible that the heater is actually pulling a bit more than it's listed at.
 
Lazy Daze said:
Yup - if you want to confirm, just look at the breaker for the system. Or, another way to tell is by looking at the outlet. You know what a 15a outlet looks like because it's the one in your boat. Google for a 20a outlet and you'll see the difference. You can plug a 15a item into a 20a receptacle, but you can't physically plug a 20a item into a 15a receptacle.

If you look around your house, you should see a difference, too. If you look at the outlets around your kitchen counter top, those are typically 20a outlets (unless the wiring is really old and hasn't been updated in a long time).

In a nutshell, if the heater has a "normal" plug (15a), you're good.
Click to expand...

Thank you! So as long as that circuit isn’t pushing beyond 15a, and the DF panel isn’t pushing beyond 30a, then I’m safe to attribute 1000w for a space heater to the dinette outlet, you’d think?
 
jmauld said:
Mine are also rated at 15A. As a good practice, you should not load a receptacle more than 80% of it's rating for long periods.

So, limit the load to 12A, or about 1300-1400watts. Also keep in mind that most dock electrical systems are poor, and you're probably not getting 120 V to your boat. If the voltage is too low, some of your devices may operate out of spec, so keep an eye on that.
Click to expand...

I’m trying to appreciate each reply but see crossover in several of the responses. Thank you for this, this is great feedback.

What’s my worst case of the load is too heavy, surges, or I forgot I have something else on that circuit? Just a trip?

I suppose my specific question WO having enough knowledge is: can I harm crucial comments like my inverter from this space heater?
 
Stee6043 said:
My direct experience - you cannot run a 1500W space heater on "high" on a Sea Ray circuit for more than a few minutes before the breaker will pop. If you end up buying a 1500W heater make sure it has multiple output settings.

For me low seems to work perfectly. I imagine that's around 1000W +/- on the Honeywell unit I run during the shoulder seasons.
Click to expand...
Thank you, trying to learn as I go. This specific example really helps!
 
Lazy Daze said:
Another factor is that GFCI's and breakers tend to pop more often as they age. They, like us, simply get worn out! It's also possible that the heater is actually pulling a bit more than it's listed at.
Click to expand...
Thanks for the added context, I appreciate everyone’s willingness to support my learning and experience!
 
Gregory Beach said:
What’s my worst case of the load is too heavy, surges, or I forgot I have something else on that circuit? Just a trip?
Click to expand...
Circuit tripping is your best case. Worst case, your boat catches on fire, and burns down the entire marina, which is under insured.
But there are protections in place to keep that from happening. :)
 
jmauld said:
Circuit tripping is your best case. Worst case, your boat catches on fire, and burns down the entire marina, which is under insured.
But there are protections in place to keep that from happening. :)
Click to expand...
:D
 
jmauld said:
Circuit tripping is your best case. Worst case, your boat catches on fire, and burns down the entire marina, which is under insured.
But there are protections in place to keep that from happening. :)
Click to expand...

Well that escalated quickly!

This reminds me of a call I made to my insurance provider a couple years back. I increased my total liability limit on my boat policy and increased my umbrella amount after a boat in our marina burned. The total bill was in the millions. The marina's insurance had nothing to do with any of it - it all came down to the boat owners and their policies.
 
Gregory Beach said:
Thank you! So as long as that circuit isn’t pushing beyond 15a, and the DF panel isn’t pushing beyond 30a, then I’m safe to attribute 1000w for a space heater to the dinette outlet, you’d think?
Click to expand...
Yup, you'll be fine. Unless the wiring has been hacked, the risk of fire (which of course is not a myth) is EXTREMELY low. Like, really, REALLY low. Old wiring/hacked wiring... that's a different scenario.

Quick and to the point... don't worry about the rating of the heater or the setting. If the plug fits, plug it in and get warm.
 
I would like to add just one thing to what L.D. said. Make sure the heater has a third party mark, and not the “CE” mark. Look for a UL, ETL or CSA mark on it. Particularly if you’re buying from Amazon/eBay as they do not monitor the goods they sell for safety marks.
 
jmauld said:
I would like to add just one thing to what L.D. said. Make sure the heater has a third party mark, and not the “CE” mark. Look for a UL, ETL or CSA mark on it. Particularly if you’re buying from Amazon/eBay as they do not monitor the goods they sell for safety marks.
Click to expand...
Thanks for this reminder, friend! A very good point and I’m grateful you shared.
 
Stee6043 said:
Well that escalated quickly!

This reminds me of a call I made to my insurance provider a couple years back. I increased my total liability limit on my boat policy and increased my umbrella amount after a boat in our marina burned. The total bill was in the millions. The marina's insurance had nothing to do with any of it - it all came down to the boat owners and their policies.
Click to expand...
Yikes, that's awful! Thanks for that advice and forewarning.
 
Lazy Daze said:
Yup, you'll be fine. Unless the wiring has been hacked, the risk of fire (which of course is not a myth) is EXTREMELY low. Like, really, REALLY low. Old wiring/hacked wiring... that's a different scenario.

Quick and to the point... don't worry about the rating of the heater or the setting. If the plug fits, plug it in and get warm.
Click to expand...
Thanks for balancing my frantic mind with a little gravity here, I appreciate you!
 
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