2020-033 Windhaven Transmission PoleDate: April 10, 2020 Report No. 2020-033
INFORMAL STAFF REPORT
TO MAYOR AND CITY COUNCIL
SUBJECT:
Windhaven (Split Rock Drive) Transmission Pole
BACKGROUND:
A potential violation of the National Electric Safety Code (NESC) for clearance has been
documented along the 138 kV transmission line through the Windhaven subdivision in Southeast
Denton. On February 18, 2020 the Denton City Council received a work session presentation
from Denton Municipal Electric (DME) on the situation and provided staff with direction to
proceed with the installation of a single transmission pole to abate the violation. However,
Council also requested additional clarification on certain survey discrepancies before installing
the new transmission pole. Staff provided the requested survey information to Council on March
3, 2020. Council’s direction was unchanged. Subsequent to the March 3, 2020 work session, the
home owner corresponded with Council suggesting that DME pursue an alternative to
installation
DISCUSSION:
Homeowners of the affected residence on Split Rock Drive provided an email to Council
members suggesting that DME perform more accurate survey data and consider removal of part
of the awning of their home in order to achieve the required NESC clearances. DME did a
preliminary assessment of this potential option and has rejected it for the following reasons:
1. The prior work to determine the distances from the line to home was done by our
surveyors using very accurate measurement techniques that limit error to within two
inches. Thus, no need for further surveying work.
2. The corner of the second floor of the home would need to be modified by at least 3 feet
which is more than the dimension of the eave of the house. This would require structural
engineering of the load bearing walls that would require modification, architectural work,
permitting, contracting, etc. Costs would be a minimum $30,000 and more likely in
the $50,000 range.
3. The reduction in square footage and visual impairment to the home would likely reduce
the homes’ value, despite the investment to make the changes and thus the homeowner
would be trading off perceived reduced value from the new pole (alleged reduction in
home value) with reduced home value due to the modifications necessary.
4. The NESC minimum clearance requirements are just that, MINIMUM. The standards
state that the operator of the transmission system shall “determine any additional required
safety buffer”. If the home were modified to address the minimum clearance standard, it
leaves no safety buffer. Raising the line provides what DME considers an acceptable
safety buffer.
a. The aluminum gutters on the home are seamless and in the event they are ever
removed from the home, it is not unrealistic to be concerned that the 30-foot
Date: April 10, 2020 Report No. 2020-033
aluminum gutter could be caught by the wind or inadvertently moved in contact
with the 138,000 volt line. The single pole option raises the line sufficiently high
enough to mitigate this potential.
b. Even if the home were modified to achieve the clearance requirements, erecting a
ladder to access the roof of the front porch or the second floor would place the
ladder and the person on the ladder inside the minimum clearance requirement
and poses risk of personal injury should the ladder fail or if the individual on the
ladder is carrying anything that is conductive.
The pole construction must be completed and the circuit re-energized prior to May 15th to
comply with ERCOT restriction on transmission outage during high demand periods. The
outage must be pre-scheduled with ERCOT to ensure that other scheduled system outages don’t
impact the reliability of the grid. DME does not have the equipment to erect the new pole and
must contract the work. The work must be scheduled as soon as possible to ensure that the
foundations, pole erection, line transfer and outage can be concluded by May 15, 2020.
Additionally, the recently passed HB 4150 requires owners of transmission and distribution lines
to certify compliance with the NESC clearance standards on May 1, 2020. As the owner of the
line, TMPA will have to report the non-compliance and the mitigation plan to the Public Utility
Commission of Texas (PUCT) by May 1. If the work can be completed by that time, the
certification can be made without contingency or exception.
Discussion with the homeowner indicates that the proposed location of the new transmission
pole will not interfere with the existing gate that opens onto the easement.
DME ACTIONS:
DME will immediately begin scheduling the work with our contractor and once a schedule has
been finalized with both the contractor and ERCOT, we will inform the homeowner of when the
work will begin.
STAFF CONTACT:
Terry Naulty
Assistant General Manager
Denton Municipal Electric
Terry.naulty@cityofdenton.com
(812) 972-1457 mobile