Meter probes incorporating integral fuse holder which contains limitation fuse of 600 V, 5A, with interruption rating of 50,000 KVA. provide required protection and minimize danger incurred by defective or improperly operated meter

Getsug, J.

Long, H.

English

NASA Technical Reports Server

August 1972
	
B72-10455 
•	 NASA TECH BRIEF 
Langley Research Center 
NASA Tech Briefs announce new technology derived from the U.S. space program. They are issued to encourage 
Commercial application. Tech Briefs are available on a subscription basis from the National Technical information 
Service, Springfield, Virginia 22151. Requests for individual copies or questions relating to the Tech Brief program may 
be directed to the Technology Utilization Office, NASA, Code KT, Washington, D.C.20546. 
New Meter Probes Provide Protection From High Current Power Sources 
at Potentials Up to 600 Volts 
The problem:	 The solution: 
If a faulty test instrument or improper operational Use meter probes which incorporate fuses with 
procedure is used in testing high current power an interruption rating that is high enough to open 
sources, the test instrumentation can draw an ex- the meter circuit prior to ionization and before the 
short-circuit condition can occur. 
tremely high urrcllt, resulting in an arc across 
the test lead tips. This arc can initiate ionization 
which can short-circuit the power source; the short-
circuit can become self-propagating; and the high 
current can severely burn operating personnel. 
Though fuses are used on some conventional multi-
testers, they do not have the interruption rating 
required to limit the short-circuit current from the 
power source when high current is involved.
How it's done: 
The meter probes incorporate an integral fuse-
holder which contains a limitation fuse of 600 V, 
5A, with an interruption rating of 50,000 kVA. An 
analysis of test data on this probe indicates that it 
provides the required protection and minimizes the 
danger incurred by a defective or improperly operated 
meter. Meter accuracy is unaffected within the normal 
range of the instrument, but a current range of 
over 5 A is not usable. 
Note: 
No additional documentation is available. Specific 
questions, however, may be directed to: 
Technology Utilization Officer 
Langley Research Center 
Hampton, Virginia 23365 
Reference: B72-10455 
Patent status: 
Inquiries about obtaining rights for the commercial 
use of this invention may be made to: 
Patent Counsel 
Mail Code 173 
Langley Research Center 
Langley Station 
Hampton, Virginia 23365 
Source: H. Long and J. Getsug
Langley Research Center 
(LA R-10804)
Category 01 
I'
Test Leads 
/ `1	
Holder 
Probe 
Assembly 
This document was prepared under the sponsorship of the National 	 Government assumes any liability resulting from the use of the 
Aeronautics and Space Administration. Neither the United States	 information contained in this document, or warrants that such use 
Government nor any person acting on behalf of the United States 	 will be free from privately owned rights.
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New meter probes provide protection from high current power sources at potentials up to 600 volts

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