point of connection [RE-wrenches]

[Bill Brooks]

Dick,

In general you are correct, (with few exceptions, e.g. a PV system) but the
NEC permits multiple services under 230.2(A) Special Conditions.

230.2 Number of Services. A building or other structure
served shall be supplied by only one service unless permitted
in 230.2(A) through (D). For the purpose of 230.40, Exception
No. 2 only, underground sets of conductors, 1/0 AWG and
larger, running to the same location and connected together at
their supply end but not connected together at their load end
shall be considered to be supplying one service.
(A) Special Conditions. Additional services shall be permitted
to supply the following:
(1) Fire pumps
(2) Emergency systems
(3) Legally required standby systems
(4) Optional standby systems
(5) Parallel power production systems
(6) Systems designed for connection to multiple sources of
supply for the purpose of enhanced reliability

Bill.

-----Original Message-----
From: Dick Ratico [mailto:Richard.L.Ratico at VALLEY.NET] 
Sent: Saturday, May 03, 2008 7:20 AM
To: RE-wrenches at topica.com
Subject: RE: point of connection [RE-wrenches]


A building, with few exceptions, is allowed only one SERVICE. The code
allows up
to six grouped disconnect switches PER SERVICE.  A PV disconnect is to be
counted among the six, not as an additional service. NEC 230.79 specifies
the
rating of the total service, not the ratings of the, up to six, individual
disconnects which make it up. If there was only one disconnect on a one
family
dwelling, and it was a PV disconnect, it would be required to be "not less
than
100 amperes, 3-wire". 

However, if that dwelling has a second disconnect to supply the loads in the
structure, the intent of the code is obviously for that disconnect to be not
less than 100 amperes. In that case, the other disconnect in that service,
the
PV disconnect, and it's conductors are specified by article 690.8(B)(1),
125% of
the maximum inverter output circuit current. This, of course, can be much
less
than 60 amps.

Respectfully,

Dick Ratico
Solarwind Electric
Bradford, VT


- - - -
Hosted by Home Power magazine

To send a message: RE-wrenches at topica.com

Archive of previous messages: http://lists.topica.com/lists/RE-wrenches/read

List rules & how to change your email address: www.mrsharkey.com/wrenches/etiquette.php

Check out participant bios: www.mrsharkey.com/wrenches/

Moderator: michael.welch at homepower.com
--^----------------------------------------------------------------
This email was sent to: michael.welch at re-wrenches.org

EASY UNSUBSCRIBE click here: http://topica.com/u/?bz8Qcs.bz9JC9.bWljaGFl
Or send an email to: RE-wrenches-unsubscribe at topica.com

For Topica's complete suite of email marketing solutions visit:
http://www.topica.com/?p=TEXFOOTER
--^----------------------------------------------------------------