Fixing Electric Wiring in Schools: A Video
Due to public concern regarding electric and magnetic field (EMF) exposure and children's health, the California EMF Program has focused attention on EMF in schools. To determine EMF levels and sources in California public schools, the California EMF Program conducted the California School Magnetic Field Exposure Assessment Survey. While collecting EMF measurements for this survey, it was discovered that many of the 89 schools surveyed had improperly connected electrical wiring. Not only are these wiring errors the most common source of elevated magnetic fields in schools, but they may violate state and local electrical codes and could be a potential fire hazard.
It is currently unknown whether EMF is a health hazard. However, by evaluating electrical
breaker boxes, schools can determine whether their wiring violates electrical codes, and should,
therefore, be corrected.
Wiring should not produce elevated magnetic fields or pose a fire hazard. When wires are connected correctly, currents of similar levels flow in opposite directions in the circuit and their fields "cancel each other out." However, improperly connected wiring can cause one wire to contain a much stronger current than the other. This discrepancy prevents the currents from "canceling out," resulting in a net current and strong magnetic fields.
Strong magnetic fields could cause the insulation surrounding the conductor to overheat and
prematurely age. If aged, the insulation can become brittle and may no longer be able to
contain the current. Short circuits could then result, some of which could arc. When a short
circuit or arcing occurs, the current is not contained by the insulation, and, consequently,
resulting sparks or the heat from the wires could initiate a fire. Additionally, improper wiring
could pose a shock hazard or interfere with nearby electrical devices.
Although improperly connected wiring may not pose an immediate hazard, it is an issue that
should be addressed. To help schools understand and potentially fix wiring problems, EMF
consultant Karl Riley demonstrates techniques for recognizing and correcting these problems
in a training video sponsored by the California EMF Program and Southern California Edison.
The California Department of Education mailed this video to every California school district in
April of 2000, along with a short document further explaining wiring errors and a set of pre- and
post-training questions and answers to assess electricians' understanding of this issue.
Unfortunately, it may be difficult to find electrical consultants who are very familiar with the wiring errors and their
correction techniques described in the video. There is also no state agency that could provide further expert assistance on this topic. Therefore, it is our intent that the video and supplementary documents serve as important tools in assisting electricians. School districts may want to establish a regional training program for their staff to
develop the needed electrical expertise in identifying and fixing these problems.
The wiring video was created as a result of fire safety concerns. Although repairing wiring connections will eliminate high EMF, the primary justification for correcting wiring errors in the near future is a concern for fire safety.
To reduce costs, the Department of Education recommends that the repairs mentioned in the video and supplementary documents be carried out during routine maintenance and modernization projects, as electrical work would already be occurring.
Since it is not known at this time whether EMF exposure causes health problems or how serious wiring problems could
be, materials distributed through the EMF Program do not provide the key to making a school "safe." However, they
will alert you to possible hazards, and ways in which these possible hazards could be alleviated.
1515 Clay Street, Suite 1700 Oakland, CA 94612