Go Back   DIY Chatroom Home Improvement Forum > Home Improvement > Electrical

CLICK HERE AND JOIN OUR COMMUNITY TODAY...IT'S FREE!

Reply
 
Thread Tools Search this Thread Display Modes
Old 01-10-2012, 07:33 PM   #1
Newbie
 
Join Date: Jan 2012
Posts: 4
Share |
Default

100 Amp Service with 2 80A Breakers


I have access to the main panel that has a 100A service. I am installing 4 outdoor electric heaters. Each "set" of heaters requires a dedicated 240V 80A Breaker. I will need two of these "sets" therefore two 240V 80A breakers. Each heater is 6000W which would calculate out to 25A each. If all four were running at the maximum level, that could use the entire 100 Amps.

The main panel also contains 50A breaker for a spa, 30A for pool equipment, 30A for A/C and various 15/20 breakers for kitchen appliances.

Do I need to upgrade to a 200A service?

DVLand is offline   Reply With Quote
Old 01-10-2012, 07:59 PM   #2
Electrical Contractor
 
kbsparky's Avatar
 
Join Date: Sep 2008
Location: Delmarva
Posts: 3,368
Default

100 Amp Service with 2 80A Breakers


Yup.... maybe more ...

__________________
-KB

Life is uncertain -- eat dessert first!!
kbsparky is offline   Reply With Quote
The Following User Says Thank You to kbsparky For This Useful Post:
DVLand (01-10-2012)
Old 01-10-2012, 08:03 PM   #3
MarginallyQualified
 
Join Date: Dec 2011
Location: Winston-Salem NC
Posts: 3,656
Default

100 Amp Service with 2 80A Breakers


Quote:
Originally Posted by DVLand View Post
If all four were running at the maximum level, that could use the entire 100 Amps.
Maybe I lost track of that watt/amp load... but I'll take you word for the math.

The main panel also contains... spa, pool equipment, A/C and various 15/20...
Do I need to upgrade to a 200A service?
I'd say no less than 200A.
Have you considered some other type of heater?
TarheelTerp is offline   Reply With Quote
Old 01-10-2012, 08:08 PM   #4
Newbie
 
Join Date: Jan 2012
Posts: 4
Default

100 Amp Service with 2 80A Breakers


The heaters were spec'ed by someone else. The nice thing about electric heaters is that you can control the heat intensity. My other option would be gas but those are either "On" or "Off." No in between. However, if the cost of running a new service is too much, I will have to go gas.
DVLand is offline   Reply With Quote
Old 01-10-2012, 08:10 PM   #5
Floor Sweeper
 
Join Date: Nov 2007
Location: Central MN
Posts: 353
Default

100 Amp Service with 2 80A Breakers


If you decide to go electric, take a look at the operating costs as well.

What do these heaters heat?
junkcollector is offline   Reply With Quote
Old 01-10-2012, 08:15 PM   #6
Newbie
 
Join Date: Jan 2012
Posts: 4
Default

100 Amp Service with 2 80A Breakers


People. These are inside an open sided pavilion. It's an outdoor kitchen, BBQ, and Fireplace that is covered. There are supposed to be 4 heaters. I agree, gas is much cheaper to run.

I really appreciate the quick responses from this group. Thanks.
DVLand is offline   Reply With Quote
Old 01-10-2012, 08:24 PM   #7
Licensed Electrical Cont.
 
Speedy Petey's Avatar
 
Join Date: Feb 2004
Location: NY State
Posts: 6,798
Default

100 Amp Service with 2 80A Breakers


Who is spec'ing these? Where are they going? And who is doing the wiring?

I assume this is not a residence, so I truly hope a qualified electrician is doing the wiring.
The fact that you are asking if you can add 24,000 watts, or 100 continuous amps, worth of electric heat to a 100A panel with a 50A breaker for a spa, 30A for pool equipment, 30A for A/C already in it says to me that you might not be qualified to do this work.
__________________
Sometimes I feel like if I answer any more questions it is like someone trying to climb over a fence to jump off a bridge and me giving them a boost.
Answers based on the 2008 & 2011 NEC.
Speedy Petey is online now   Reply With Quote
Old 01-10-2012, 08:28 PM   #8
Member
 
Missouri Bound's Avatar
 
Join Date: Apr 2011
Location: Almost Arkansas
Posts: 2,764
Default

100 Amp Service with 2 80A Breakers


Quote:
Originally Posted by DVLand View Post
The heaters were spec'ed by someone else. The nice thing about electric heaters is that you can control the heat intensity. My other option would be gas but those are either "On" or "Off." No in between. However, if the cost of running a new service is too much, I will have to go gas.

Go to gas. The electric upgrade required could possibly be a 400 panel....start checking costs and gas will make the most sense.
Missouri Bound is offline   Reply With Quote
Old 01-10-2012, 08:30 PM   #9
Newbie
 
Join Date: Jan 2012
Posts: 4
Default

100 Amp Service with 2 80A Breakers


Actually, it is a residence. I'm overseeing the project and wanted to address potential areas of concern prior to getting too far. This looked like a red flag to me so I wanted to make sure my instincts were correct. And "Yes", an electrician will be called in to do the installation as this work will need to be permitted.
DVLand is offline   Reply With Quote
Old 01-10-2012, 08:52 PM   #10
Semi-Pro Electro-Geek
 
Join Date: Jul 2009
Location: Arizona, USA
Posts: 2,542
Default

100 Amp Service with 2 80A Breakers


Plenty of variable gas heaters exist (for example, every gas patio heater I've ever seen), and plenty of electric heaters are not continuously variable. I'd have them select gas heaters.
mpoulton is offline   Reply With Quote
Old 01-10-2012, 09:39 PM   #11
Member
 
bubbler's Avatar
 
Join Date: Oct 2010
Location: North Shore MA
Posts: 481
Default

100 Amp Service with 2 80A Breakers


Quote:
Originally Posted by DVLand View Post
I have access to the main panel that has a 100A service. I am installing 4 outdoor electric heaters. Each "set" of heaters requires a dedicated 240V 80A Breaker. I will need two of these "sets" therefore two 240V 80A breakers. Each heater is 6000W which would calculate out to 25A each. If all four were running at the maximum level, that could use the entire 100 Amps.

The main panel also contains 50A breaker for a spa, 30A for pool equipment, 30A for A/C and various 15/20 breakers for kitchen appliances.

Do I need to upgrade to a 200A service?
Let's see, four 6000W heaters would be 24000W, or 100A as you said

Another 120A between the spa, pool and a/c... even we only assume that they draw 50~80% of the breaker rating that's still another 60-100A.

Typical residential Kitchen needs a minimum of two 20A for the counters... another 15A for the microwave... have a dishwasher (15A)?... have a disposer? Some lights... we're looking at 50-80A for the kitchen...

Sounds like you a candidate for the 320A meter socket with 400A panel.
__________________
My advice is based on anecdotal knowledge or personal experience. I'm not a professional no matter how matter of factly I may say something
bubbler is offline   Reply With Quote
Old 01-11-2012, 12:39 AM   #12
Semi-Pro Electro-Geek
 
Join Date: Jul 2009
Location: Arizona, USA
Posts: 2,542
Default

100 Amp Service with 2 80A Breakers


Quote:
Originally Posted by bubbler View Post
Let's see, four 6000W heaters would be 24000W, or 100A as you said

Another 120A between the spa, pool and a/c... even we only assume that they draw 50~80% of the breaker rating that's still another 60-100A.

Typical residential Kitchen needs a minimum of two 20A for the counters... another 15A for the microwave... have a dishwasher (15A)?... have a disposer? Some lights... we're looking at 50-80A for the kitchen...

Sounds like you a candidate for the 320A meter socket with 400A panel.
That's really not how a load calc works. The heaters are, in fact, 100A - we know that from their ratings. The spa, pool, and AC will all use considerably less than their breaker ampacities, and the kitchen loads even less so. A pool pump is almost always under 10A at 240V. A spa with heat is often 40A or so with the heat on. Air conditioners often have very large breakers sized to the compressor's LRA rather than the actual load, so that can be very misleading. The kitchen loads have considerable diversity. The microwave, dishwasher, and garbage disposal will not run together for any length of time. The entire kitchen load, excluding any electric ranges or ovens, should not exceed about 3kW - and remember that those are 120V devices, not 240, so the service amperage is half what you might add up.

I would think a 200A service is adequate for this. Especially since the electric heat will not be used at the same time as the air conditioning. Bottom line: if a 100A service was adequate before adding the heaters, then a 200A service will be adequate after.

But I still think gas is a much better choice.

mpoulton is offline   Reply With Quote
The Following User Says Thank You to mpoulton For This Useful Post:
Speedy Petey (01-11-2012)
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
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


Similar Threads
Thread Thread Starter Forum Replies Last Post
Service entrance for farm house. jptkaczyk Electrical 14 02-12-2011 05:24 PM
Service mast options bsperr Electrical 6 12-09-2009 08:48 AM
Grounding for two service entrances to same house. jogr Electrical 18 09-24-2008 10:31 AM
Wire size for Sub panel DaleB Electrical 13 09-18-2008 12:28 AM
2x100a sub on service main jambud Electrical 17 03-12-2008 09:31 AM




Top of Page | View New Posts

Copyright © 2003-2014 Escalate Media. All Rights Reserved.