Electrical
Environmental
Conduit will not physically change by switching to
The environmental field has been progressive regarding
metric. It becomes classified by a nominal mm size.
SI. Many regulations have been metric for years.
There has been significant discussion among our
Based on review of commonly used environmental data,
partners at NEMA and in the conduit manufacturing field
projects shall now specify metric only.
regarding designations of various conduit types.
Estimating
Most important is these products will be physically
identical. Look to NEMA for future guidance.
Time We find metric design and construction take the
same number of months as english projects. No
Wire Size Almost all cable firms contacted make metric
adjustments have been made to time expectations.
sizes for export, or can make them.
Minimum orders vary.
Cost Estimating shall be done in metric units only.
Projects with medium and larger wire requirements may
Design Costs There will be no change to the standard
wish to start using international sizes, where permitted
design fee charts used to calculate design costs.
by governing codes and criteria.
Now that 1) specs are SI 2) SI estimating tools are
Many projects have begun to refer to existing sizes by
offered 3) criteria is SI 4) most codes and standards
mm2 dimensions, to become familiar with mm2 scale.
have SI 5) sample drawings exist for most items, we
cannot justify uniform premiums for metric design.
These are mm2 equivalents with detailed rounding. In
some cases, rounding to nearest 0.1, 1, or more mm2
Construction Costs Bids to date have not shown
may be feasible. Use professional judgement.
detectable premiums for metric. No additional funds are
being allocated for metric construction.
AWG-mm2 22-0.506 20-0.517 18-0.82 16-1.31
14-2.08 12-3.31 10-5.26 9-6.6 8-8.37 7-10.6
We would welcome comparing detailed cost analysis
6-13.30 5-16.8 4-21.15 3-26.66 2-33.63 1-42.41
which yields results contrary to this conclusion.
1/0-53.48 2/0-67.44 3/0-85.03 4/0-107.2
Estimating Tools are offered by many prominent firms.
kcm-mm2 250-126.68 300-152.01 350-177.35
400-202.68 450-228.0 500-253.4 550-278.7
Building System Design GA, offers metric estimating
600-304.0 650-329.4 700-354.7 750-380.0
software. Larry Hendrix 404-876-4700
800-405.4 900-456.0 1000-506.7 1100-557.4
1200-608.1 1250-633.4 1300-658.7 1400-709.4 1500-
Cost Engineering Technologies NJ, offers a metric
760.1 1600-810.7 1700-861.4 1800-912.1 1900-962.7
database. Kenneth Browne 201-335-1707
2000-1013.4
MCASES Gold, DOD database, operates in metric.
ASTM B682 gives metric sizes. Common sizes are:
MC2 (MC Squared) TN, offers a metric database.
0.5, 0.75, 1, 1.5, 2.5, 4, 6, 10, 16, 25, 35, 50, 70, 95, 120,
Billy Telford 901-346-9880
150, 185, 240, 300 mm2
R.S. Means MA, 800-448-8182, offers metric estimating
Fiber Optics It was falsely reported in the last edition
handbooks. Database available in late 1993.
that fiber optic cables would be soft converted. Most
cables are made to metric dimensions, so these will be
Timberline OR, offers a metric database.
specified in hard metric. (ex, 125 um fiber cable)
Ann Kenkel Curtis Peltz 503-626-6775
Illumination levels are in lux (lx). Specify lux values
US Softcost GA, offers their Success metric database.
using the rachet technique, where feasible and allowed
Louis Parkins John Williams 800-955-1385
by criteria. 1 FC ~ 10 lx; thus rounding a few lx may
have little impact.
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