How do I determine the size (amps) of my electric meter panel? And how many circ

[eddiescabin]

Onward with my rebuild of a 1924 REDWOOD MILLED LOG CABIN that is planned 24 X 30 plus 12x24 top floor.  This will have electric tankless water heater, electric dryer as well as capability for multiple outlets, lighting and shop/shed  (nothing high power) requirements.  Just wondering if I need 125 amp, 200amp etc.  Thanks

[Fred_47460]

Many of the answers for your questions will be available from your local building code people. For example: How many outlets per foot of wall space and the number of outlets per circuit breaker. You don't want adjacent rooms lighting circuits to be on the same breaker. Tankless water heater, cloths dryer, and electric range require 240 Volts....the circuit breakers for 240 Volts take up 2 (TWO) slots in your breaker panel.

Set down with a rough floorplan of your house and draw where you will want outlets, lighting, etc.
Use the info you get from the code police to decide how many circuits you will need. Leave room for expansion! Don't max out your panel....leave slots for future desires. If the code says 7 outlets per breaker, only use 5 per breaker....in case you find the desire to add outlets to the circuit later.

I would not use less than a 200 Amp panel for the number of 240 Volt devices you've already mentioned.

[MountainDon]

THIS may help

[eddiescabin]

Thanks for the info!  Much of it I know, yet have made a concerted effore not to have to buy something twice or do work twice if it can be avoided.  With the electric service panel size (amps) and # of circuits required, I do notice the different brands matter also, as the require certain types/brands of circuit breakers...lead in to the   what brand of circuits is the best and what makes them more desireable than another brand, also, notice the costs vary greatly too.  Any answers?  Thanks Again

[MountainDon]

Square D

[muldoon]

I agree with Don on the squareD recomendation, but I would add they have two lines.  The homeline and the Q0 line.  The homeline is a company they purchased and integrated into their product lineup, while the Q0 line is the old squareD that is what their reputation is built upon.  I went with the Q0 series. 

[MountainDon]

muldoon is right; I should have spec'd QO.    It's what I've used, home and cabin.

[eddiescabin]

I do recognize the Square D brand from my searching Home Depot...but what aspects of the brand and Qo line make them better/more desireable? 

[MountainDon]

Square D has a wide range of products; it may just be me but I like that, even though I know I'll never use most of what they make.  I believe they have a 10 year warranty. They have a reputation among electricians as a very good product; at least among the few I know around here.

[sdhyde]

What area of the country is the cabin located?  An electric tankless needs 120-150 amps by itself (for a model that will serve more than a single use at a time).  Climate will help determine which model to use there.  Out here in the Pacific NW, the best you can do with electric tankless is about 3 gpm at 120 degrees.  That model requires 150 amps (3-50 amp circuits).

[eddiescabin]

Hi, SDHYDE, we are in the Bay Area, but do know of many 3000 to 7000 sq ft homes here that have tankless electric.  I could go with nat gas also, depending on the efficiencies.  Just wanted the electric option as far as electric panel size/amps.  I always want to over build and leave the most options available if I havent decided exactly (ie gas vs electric)  Thanks, this would be a multi use 2 bath at least

[ChuckinVa]

I do recognize the Square D brand from my searching Home Depot...but what aspects of the brand and Qo line make them better/more desireable? 

Square D  QO breakers have a Visitrip feature that has a little window on the face of the breaker and when the breaker trips there is a red flag that appears in the window. It is easily seen when you are looking in the load center with a flash light trying to tell which breaker tripped ! The QO load center has copper bus, split neutrals and the main breakers are rated 22KAIC Standard. :-)

[sdhyde]

I did some work in the Bay area some years ago and it is considerably warmer there (even though it's always freezing in SF) than here.  You would see considerably better performance there with an electric model.  I am a plumber, and I specialize in tankless water heater systems here in the Seattle area.  We have researched and installed several brands of electric tankless systems, and the Stiebel Eltron Tempra 36+ is the only one we would endorse here in our climate.  I would guess in your climate you could expect 5 or so gpm at 120 degrees.  Up here, they will give about 3-3.5 gpm.  It takes about 2 gpm of hot water for the "average" shower.  The 36+ draws 150 amps, (you need 3-60 amp breakers with  6 gauge conductors).  Natural gas fired systems are of course WAY better in every category.  (well, maybe not price).  

http://www.stiebel-eltron-usa.com/techdata_tempranew.html

I am in the planning stages of building the 1.5 story on my property on the Washington coast.  I haven't decided which hot water system I will use.  I may go with a radiant heating system, but there is no natural gas there.  Propane is SOOO expensive here in our area, so I cringe at the thought there.  I also want a system that I can run off a generator, so the elect tankless is out for me.  Decisions decisions...

[eddiescabin]

SDHYDE, Thanks, that is exactly the info I need in making a decision.  Of course, I am considering the likelihood of another "electric crisis' here in Cali, but I am acutely aware that some great guiding hand rools the dice to determine if it will be an electric crisis, or maybe a natural gas, a water crisis maybe...even a gasoline...we get it all here!  I do also wonder about a "doomsday" scenerio where after the quake there might not be a gas line, heck even a water line!  Ha ha, funny to jest, but these things do happen.  Im actually leaning toward the Natural gas.  Do all of this type require an outside vent?  It is not a problem for my design either way as it will be mounted on back downstairs wall.  Also, I had not heard of the brand you recommend, I have seen the Bosch, which I was planning on buying the best available, despite price. Thanks, Eddie

[sdhyde]

Im actually leaning toward the Natural gas.  Do all of this type require an outside vent?  It is not a problem for my design either way as it will be mounted on back downstairs wall.  Also, I had not heard of the brand you recommend, I have seen the Bosch, which I was planning on buying the best available, despite price. Thanks, Eddie

All the gas fired models do vent, and therefore must either be mounted outside or vent through the wall to the outside.  I recommend ONLY going with a direct vent style of gas tankless if the unit is inside the living space.  The outdoor mount is a great way to go if you don't have the potential for freezing.  We install outdoor mounts here in Seattle even though we do get cold once in a while, but our preference is to always use an indoor model whenever possible.  Noritz is our favorite line of tankless systems, but there are other brands that work well too.  Best?  The Noritz N-084 MC DV.  (IMHO)