HomeMy WebLinkAboutWATTAGE WORKSHEET WNGenerator Installation Check List
Per National Electrical Code, Article 702, Optional Standby Systems
Contractor: -------------------Permit#: -------------
Property Address ________________________________ _
EXAMPLES:
SERVICE SIZE AMPS 200AMPS
GENERATOR SIZE KW 20KW
GENERATOR AMPS 85AMPS
SWITCH TYPE AUTOMATIC/ MANUAL
200 Automatic Transfer Switch
National Electrical Code Article: 702.5(8)(2)(a) Automatic Transfer Equipment
Full Load: The stand by source shall be capable of supplying the full load that is transferred by the automatic
transfer equipment.
Provide Load Calculations for review. (National Electrical Code 220.83 Existing Dwelling):
EXAMPLES:
Square Feet of Living Area Sa. Ft. 3726 Sq. Ft
Sq. Ft. of Li vina Area x 3va 11,178
Kitchen Special (@. 1,500 2 Kitchen special ® 3,000
Refrigerator @ 1 Refrigerator (@.1 ,500
Laundry@, 1 Laundry @, 1,500
Range@ 1 Range (a) 8,000
Water Heater 4,500
Dishwasher 1,440
Garbage Disposal 960
Clothes Dryer 5,000
AC/AHU SheddimI -See Below*
Other Loads
Total 37,078
First Bk (a) 100% = First Bk (a) 100% = 8,000
Remaining (a) 40%= Remainine (@40% = Remainina 29078 ® 40% = 11,631
Total 19,631
19631 / 240 = 81 .79 amps
Provide Load shedding description and/or schematic.
NO LOAD SHED REQUIRED
Note: Manual Transfer Equipment National Electrical Code 702.5(8)(1)
702.5 702.5(B)(1) and (2) System Capacity
•2* • Utility
source Service
Utility
Service source i U Capacity and Rating
NEC, p. 611 (TTf
* * iL-1 T Proposal 13-168
log 2741
ROP, p. 782
Standby Standby
source t source
Automatic
transfer -*•
switch
Automatic
*- transfer
switch
\
Comment 13-255
Log 114
ROC, p. 470
All loads I Standby loads Other loads
Where automatic transfer equipment is used, the source shall have a capacity
to supply the full load transferred, unless an automatic load management system
is employed that manages transferred load to within the source capacity.
Code Language Analysis and Effect
Recent natural disasters and events have resulted in the '• 702.5
increase in generator installations for commercial and in- . Capacity and Rating
dustrial applications and, specifically, for residential appli- (A) Available Short-Circutt Current Optional standby system
cations. These revisions provide clear direction about the equipment shall be suitable for the maximum available short-circuit
capacity requirements of an optional standby source that
uses automatic transfer. Substantiation with the proposal
indicated that automatic transfer equipment is being in-
current at its terminals.
(B) System Capacity. The calculations of load on the standby
source shall be made in accordance with Article 220 or by another
approved method.
(1) Manual Transfer Equipment. Where manual transfer equip
ment is used, an optional standby system shall have adequate
ferrcd. There have been significant inconsistencies in in- capacity and rating for the supply of aO equipment intended to be
terprctation of the minimum requirements that apply to operated at one time. The user of the optional standby system shall
automatic transfer switches applied in these situations. The be permitted to select the load connected to the system,
revisions now require the standby source to have a mini- (2) Automatic Transfer Equipment Where automatic transfer
mum capacity to supply the full load that is transferred by equipment is used, en optional standby system shall comply with
(2Xa) or (2Kb).
(a) Full Load. The standby source shall be capable of supplying
the full load that Is transferred by the automatic transfer equipment.
(b) Load Management. Where a system is employed that will
automatically manage the connected load, the standby source shall
have a capacity sufficient to supply the maximum load that will be
connected by the load management system.
stalled with generators that have a capacity much less than
the total load (often an entire panelboard) being trans-
an automatic transfer
switch, unless there is Change at a Glance
a load management Where optional standby
system employed that SOurces are installed using
controls the amount automatic transfer equip-
of connected load on ment, the source must be
the standby power able to carry the entire load
source. This revision served, unless automatic
provides needed clar- joa(j management systems
ification that should ^ installed,
result in designs and
installations of optional standby systems that provide suf- requirements. The revisions include rearranging
ficient source capacity that is direcdy related to the type of tfie requirements into a list format that conforms
transfer equipment selected and load management system to Section 2.1.5.1 of the NEC Style Manual.
employed.
Summary of Change
This section has been revised and reorganized
to provide a logical layout and clarify the
t
I E
i
i
367 Analysis of Changes NEC-2008