Wednesday, June 7, 2017

The Elementary Safety Book for Children

ARCAD is proud to sponsor The Elementary Safety Book for Children published by Maple Leaf Communications Inc. This free book is brought to children by businesses in local community. Do you know all the safety rules? An extensive team of animal experts show you how to play and stay safe both at home and when outside. Everything is more fun when you play safely!

Sunday, June 4, 2017

What's New? What's Changed? 2018 NFPA 70E Update

The 2018 Edition of NFPA 70E is quickly approaching. Here is a link to an article by Jim Phillips / that was recently published in the May Edition of Electrical Contractor Magazine. As usual, some changes were minor, others were quite major. There is also quite a bit of reorganization.

2018 NFPA 70E Changes Article

PS: There are changes to the definition of arc flash boundary in the upcoming NFPA 70E Standard for Electrical Safety in the Workplace. Specifically, the revised definition of arc flash boundary no longer uses the term "second degree burn" but instead "at which incident energy equals 1.2 cal/cm2.", and the revised informational note references the Stoll skin burn injury model.

NFPA 70E year 2004 assumed that the incident energy requirement increases below one second. A quote from NFPA 70E year 2004 "For situations where fault-clearing time is 0.1 second (or faster), the Flash Protection Boundary is the distance at which the incident energy level equals 6.24 J/cm^2 (1.5 cal/cm^2)." This reference was removed in NFPA 70E year 2012 edition. NFPA 70E year 2012 stated that "a second degree burn is possible by an exposure of unprotected skin to an electric arc flash above the incident energy level of 1.2 cal/cm2 ( 5.0 J/cm2 )" and assumed 1.2 cal/cm2 as a threshold incident energy level for a second degree burn for systems 50 Volts and greater. NFPA 70E year 2015 explicitly prohibited using incident energy and PPE category together. The NFPA Handbook from 2015 showed a sample label with fields to be filled in for "available incident energy" and "level of PPE" while just half a page earlier states that "available incident energy" cannot be included with the "PPE category" in table 130.7(c)15(A)(b).

The revised definition of arc flash boundary in NFPA 70E year 2018 is even more misleading. It also contradicts the accompanying revised informational note referencing the Stoll skin burn injury model. A quote from A.Stoll "Heat Transfer in Biotechnology" summarizes the issue of using a critical thermal load approach in determining arc flash boundary. The quote reads:

"Serious misconceptions have crept into this field of research through adoption of rule-of-thumb terminology which has lost its identity as such and become accepted as fact. A glaring example of this process is the “critical thermal load.” This quantity is defined as the total energy delivered in any given exposure required to produce some given endpoint such as a blister. Mathematically it is the product of the flux and exposure time for a shaped pulse. Implicit in this treatment is the assumption that thermal injury is a function of dosage as in ionizing radiation, so that the process obeys the "law of reciprocity," i.e., that equal injury is produced by equal doses. On the contrary, a very large amount of energy delivered over a greatly extended time produces no injury at all while the same "dose" delivered instantaneously may totally destroy the skin. Conversely, measurements of doses which produce the same damage over even a narrow range of intensities of radiation show that the "law of reciprocity" fails, for the doses are not equal."

Here is what ASTM F1959/F1959M Standard Test Method for Determining the Arc Rating of Materials for Clothing says about skin burn injury determination:

"12.1.4 Predicted Second-Degree Skin Burn Injury Determination (Stoll Curve Comparison) — The time dependent averaged heat energy response for each panel [..] is compared to the Stoll Curve empirical human predicted second-degree skin burn injury model:

Stoll Response, cal/cm2 = 1.1991 * ti^0.2901

where ti is the time value in seconds of the heat energy determination and elapsed time since the initiation of the arc exposure. A second-degree skin burn injury is predicted if either panel sensor heat energy response exceeds the Stoll Response value (at time ti)."

Incident energy alone has no impact on thermal damage and blast pressure. One can expose himself to any arbitrary incident energy and suffer no damage as long as the energy is delivered at slow enough rate. On the other hand, an exposure to only a fraction of 1.2 cal/cm2 may result in incurable burn provided that the energy has been delivered fast enough. Read Evaluation of onset to second degree burn energy in arc flash hazard analysis for more information. The issue of using incident energy as a measure of damage alone and without regard to the rate of the energy release has been raised to NFPA 70E committee before year 2015 edition was published but unfortunately it was never appropriately addressed by the group.

Sunday, December 18, 2016

Recommended Guidelines for Arc Flash Labeling

Whenever an arc-flash study is done or revised and new arc flash warning labels must be considered, it is a good idea to define exactly what information belongs on each label before starting to print anything. It is also a good idea to define how and where these labels will be applied before anyone peels the back off of the first adhesive label and sticks it onto anything. It is a very good idea to put those definitions into writing so that everyone who assists or who comes along later, has something to help them understand the original intent. This is particularly important as a means of trying to promote consistency and to avoid creating unnecessary confusion when an arc flash analysis study is spread out over extended period of time. A guideline document such as the one published here serves that purpose. The guideline describes how electrical equipment should be labeled, namely how many labels should be applied and in which locations, after appropriate data collection, modeling, short-circuit analysis and arc-flash study activities have been completed. The intent here is not to limit the number of labels applied but rather to insure that at least the required minimum number of labels are in place. This document also addressed the question of how to label devices that were subject to protection under a selectable maintenance settings scheme. This application involved two labels as shown in Figure 6.

The arc-flash labels discussed herein are required by the NEC in article 110.16 and by NFPA 70E in Section 130.7 (E)(1). There are two basic types of arc flash labels that should be used. They are a generic label - one that does not include specific calculated data but which identifies the existence of the hazard and refers the reader to the site 70E policy, and a specific label - one that includes calculated data for arc-flash incident energy or hazard/risk category and identifies specific required PPE. Figure 1 shows one of each type of label, with the generic type being the upper label. This guideline identifies what type of equipment we should be labeling and how to label that equipment. If a piece of equipment is identified by company guidelines as within the scope of equipment for which we should be calculating arc-flash exposure, then the label should be a specific label. Otherwise, the label will be a generic label and will refer to the overall site 70E policy. Wherever specific labels are applied, they shall describe all of the requisite PPE.

generic arc flash label
Figure 1A. An example of generic arc flash warning label.

arc flash warning label sample
Figure 1B. An example of specific arc flash warning label.

Many facilities have been through short-circuit and arc-flash studies conducted under previous versions of the NFPA 70E regulation. In such cases, it is possible that the labels already in place in the field reflect older hazard levels and types of PPE for some of the labeled equipment and are no longer correct for the current version of NFPA 70E. It is permissible to hand-modify the existing labels if the changes are somewhat minor, but it is often confusing to do that. The preferred approach is to relabel the equipment. However, since the current version of the regulation requires review and update on a five-year cycle, it is recommended that the labels simply be corrected during the course of the next overall update.

The generic label is a Brady product, while the specific label is a product printed as output from Arc Flash Analytic software program. Both of these labels use the ANSI Z535.4 "warning" format and an orange banner. The "danger" format with a red banner, described in the same ANSI standard, is equally acceptable.


Wednesday, December 7, 2016

Guide To Arc Flash Apps. Simple solutions for fast and accurate results.

Arc flash applications are increasing in popularity among engineers and electricians when examining hazards presented by an arc flash. Professionals search for accessible tools to help reduce dangers associated with arc flash as well as to assist in selecting adequate personal protective equipment (PPE). Mobile apps for arc flash analysis can be useful for assessing the hazards before working on energized equipment. 

Contrary to many simple and complex computer programs used for power system and arc flash hazard analysis, only a handful of arc flash apps are available for purchase. Each app, available in either the Apple Store (iPhone) or Google Play (Android-operated devices), vary in level of complexity and range of operations. 

Q: What are some specific benefits to workers using arc flash apps on their mobile device?

Qualified workers use mobile apps for data collection, field analysis of electrical equipment and evaluation of arc flash dangers when access to complex power system analysis computer software is limited or not available. Electrical and safety professionals can now find ways to minimize arc flash hazards using handheld gadgets while in the field by trying different protection device settings and by simulating various fault scenarios. 

The apps help in meeting the requirements of CSA Z462 "Workplace Electrical Safety" and NFPA 70E: "Standard for Electrical Safety in the Workplace" published respectively by the Canadian Standards Association and the National Fire Protection Association. Arc flash mobile apps support calculations and functions for typical distribution systems that use fuses and circuit breaker protection devices. They provide for real-time display of incident energy and arc flash boundary results

Monday, November 21, 2016

Arcad Inc. guarantees the lowest prices

We will match the advertised price of any print job from any other printer. Here are a few things you should know in order for our price matching to apply:
  • All specs for the order must be the same.
  • Price match must be inclusive of freight, shipping, and delivery if applicable.
  • We’ll need to know the URL for the competitor’s website, for verification purposes.
  • We reserve the right to decline any job that doesn’t fit within our business model.
  • We will price match up to 7 days as long as accurate proof is provided (invoice, receipt etc.)

How do you receive the matching price?

When you find another printing company that offers the same products or print service for a lower price, contact us. A friendly customer service agent will take your job specs and competing information. We’ll override the price by up to 10% provided that the price match guarantee applies.

What if I find the lower price after I’ve placed my order?

If you find a lower price that meets all of the criteria to qualify for our price match guarantee within 7 days of placing your order with Arcad Inc., please give us a call or send us an email with all your information. We will confirm all order specs and options are the same, then credit you the difference.

Thursday, November 10, 2016

The results of arc flash assessment

The arc flash analysis should result in calculated incident energy, incident energy at arc flash boundary (AFB) and AFB at each piece of electrical equipment under study. The results of the arc flash hazard analysis would typically be shown in form of the arc flash hazard table. The table shows the parameters upon which the arc flash hazard is based. Read more at

Wednesday, November 9, 2016

Protective Device Coordination Study

Properly engineered systems will allow only the protective device nearest the fault to open, leaving the remainder of the system undisturbed and preserving continuity of service. A protective device coordination study is required to properly select and set the power systems protective devices to achieve this goal. This is accomplished by performing a time current evaluation among the protective devices.
Coordination is generally a compromise between the mutually desirable but somewhat inconsistent goals of maximum protection and maximum service continuity. With the use of molded circuit breakers it is usually impossible to coordinate the system in the instantaneous region due to the overlap of curves unless a zone interlock is utilized. For this and other reasons, such as established system design, many combinations of device settings may be classified as acceptable. The settings suggested in the arc flash hazard calculation study result from an exercise of judgment as to the best balance between competing objectives. Read more at