Exiting dwellings

[epm]

Article 220.83 mentions 2 formulas for calculating loads when adding new loads to an existing service.
220.83 (A) for when no new A/C loads are added.
220.83 (B) for when new A/C loads are being added.
Does this mean that existing A/C loads can be calculated to the 40% rule of 220.83 (A)?

 

[cadpoint]

Article 220.83 mentions 2 formulas for calculating loads when adding new loads to an existing service.
220.83 (A) for when no new A/C loads are added.
220.83 (B) for when new A/C loads are being added.
Does this mean that existing A/C loads can be calculated to the 40% rule of 220.83 (A)?

Welcome to the Forum !!!

220.83(A)Where ... A/C Equipment Is Not to Be Installed

220.83(B)Where ... A/C Equipment Is To Be Instaslled

No; In answer to your question, A/C is a line item of 220.83(B) at 100%, One should stay in that Article.

Like other places in the Code, one only uses the larger of the two loads;
A/C verses the Heater load. One or the other but never both in residential.

 

[epm]

Existing dwellings

Existing dwellings

I agree that AC loads should never be calculated at 40% whether existing or new. However the way it is worded suggests that as long as AC load is "not to be installed" that all existing loads can be calculated at 40% once the 8000 VA is reached.
"Not to be installed" to me means no new AC. No mention about existing AC.

 

[jumper]

I agree that AC loads should never be calculated at 40% whether existing or new. However the way it is worded suggests that as long as AC load is "not to be installed" that all existing loads can be calculated at 40% once the 8000 VA is reached.
"Not to be installed" to me means no new AC. No mention about existing AC.

I think you are correct. Bad news, I am wrong alot.

 

[cadpoint]

I agree that AC loads should never be calculated at 40% whether existing or new. However the way it is worded suggests that as long as AC load is "not to be installed" that all existing loads can be calculated at 40% once the 8000 VA is reached.

Find your total sum Using (1-4) (forget A/C and heating for a minute)
If you had a 1000 VA load
8000 VA is @100%
2000 VA is @ 40%

this is the sum of all loads but figure out which load you need to include- the large of the existing loads does include one of a A/C or heating(number), and needs to be included to a sum of 1000VA making it even greater.

Remember your calc. a number of what's existing! re-read 230.83, or better yet look at (4) in both A and B.

There is no additional of A/C or heating (A) (no new unit , no replacement (B)((usually upsided - due to additional liviable space)) unit) .

Article 220.82(A)

"Not to be installed" to me means no new AC.

Yes

If A/C not there, then its not part of (4) in either article, nor a considertion.

 

[epm]

Existing dwellings

Existing dwellings

It seems that reaching 8000VA is pretty easy and then allowing anything additional to be at 40% including AC seems pretty liberal. It's really contrary to a new dwelling calculation where 10,000VA is at 100% and then the AC is calculated at 100% on top of that.