Splicing construction extension cords with heat-shrink covers

July 16, 1986

Mr. W. J. Conkling
Safety Director
Electrical Employers
Self Insurance Safety Plan
[Recipient address omitted]
Dear Mr. Conkling:

This is in response to your letter of June 27, requesting a clearer explanation of the acceptability of heat shrinkable insulating covers in making splices.

I have enclosed for your information and use a copy of our recently promulgated Electrical Standards for Construction.

Heat shrinkable insulating covers are acceptable in the making of splices in extension cords provided they comply with the appropriate paragraphs marked on the standards for your information (Section 1926.403(e) and Section 1926.405(g)(2)(iii)). The specific types of cord that are permitted to be spliced are listed in 1984 National Electric Code Table 400-4, first column, opposite the listings for hard service cord. (A copy of this table is enclosed for your convenience.) Examples of hard service cord include types S, SO, ST, and STO, and these designations are marked on the cord itself.

It was not the intent of our previous letter that any damaged extension cords, not being number 12 AWG or larger, must be discarded. The damaged portion of the extension cord may be removed, and the two ends may be equipped with a cord connector and an attachment plug instead of being spliced. This results in two shorter extension cords in place of the one longer cord.

If we can be of further assistance, please let us know.

Sincerely,
John B. Miles, Jr., Director
Directorate of Field Operations

[The referenced construction standards and National Electrical Code table are not reproduced on OSHA's page.]