<div dir="auto">I have installed many hundreds of Enphase CTs on live service conductors. As long as the secondary is connected first, no problem. Same with disconnecting them. <div dir="auto"><br></div><div dir="auto">Jason</div><div dir="auto"><br></div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Fri, Mar 8, 2024, 11:30 AM Sam Haraldson via RE-wrenches <<a href="mailto:re-wrenches@lists.re-wrenches.org">re-wrenches@lists.re-wrenches.org</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr">Dear Wrenches,<div><br></div><div>I'm trying to determine whether or not it is acceptable to clamp monitoring CTs around hot conductors. For this question please assume the CT wires are landed in their proper terminals and that proper PPE/safety protocol is employed. The monitored currents in question are residential services of 600A or less. Is there harm to the CT by clamping them around a hot conductor? </div><br>The physics of a CT from my brief research states that,<i> "...the secondary of a current transformer should not be disconnected from its burden while current is in the primary, as the secondary will attempt to continue driving current into an effective infinite impedance potentially generating high voltages and thus compromising operator safety." </i>This begs the question how I can use my DMM clamp meter w/o causing damage or is the italicized text related to very high current applications from the world of medium and high voltage equipment and not as pertinent to the residential and light commercial world I work in?<div><br></div><div><div>I suspect this is a no-brainer answer for the seasoned professionals on the list and I'll be most appreciative for any proof (no matter how brief) you wish to share. Ultimately we wish to minimize the need to perform power shut downs and interrupt client service when installing load monitoring CTs to a home but only wish to do so if it is part of a safe and non equipment-harming process.<br></div><div><br></div><div>Sincerely,</div><div>Sam Haraldson </div><div><br></div><div><div><div dir="ltr" class="gmail_signature" data-smartmail="gmail_signature"><div dir="ltr"><div dir="ltr"><table cellpadding="0" cellspacing="0" style="font-family:Montserrat,Tahoma,sans-serif"><tbody><tr><td style="padding:0px 10px 0px 0px;vertical-align:top"><a href="https://www.google.com/url?q=https://onsiteenergyinc.com/&source=gmail-html&ust=1677085494759000&usg=AOvVaw2NN36GoM1sjnS4RdC8Svt-" rel="noreferrer noreferrer" style="border:none" target="_blank"><img src="https://i.postimg.cc/4xVVZ5jT/email-logo.png" alt="OnSite Energy" align="top" width="85" height="85" style="display:block"></a></td><td style="padding:0px;vertical-align:top"><table cellpadding="0" cellspacing="0"><tbody><tr><td colspan="2" style="padding:0px;vertical-align:bottom"><div color="#514ca0" style="padding:0px;color:rgb(81,76,160);font-size:11pt;font-weight:600;text-transform:uppercase">SAM HARALDSON <span style="font-size:8pt"> </span></div></td></tr><tr><td style="padding:0px 5px 0px 0px;vertical-align:bottom"><div color="#f9a145" style="padding:0px;color:rgb(249,161,69);font-size:9pt">Field Operations Director</div><div color="#514ca0" style="padding:0px;color:rgb(81,76,160);font-size:7pt;line-height:8pt">(406) 551-6135<br></div><div color="#514ca0" style="padding:0px;color:rgb(81,76,160);font-size:7pt;line-height:8pt">1515 N. Rouse Ave Bozeman, MT 59715</div><div color="#f9a145" style="padding:0px;color:rgb(249,161,69);font-size:7pt;line-height:9pt">Locally owned and operated since 2012</div></td><td style="padding:0px;vertical-align:bottom"><a href="https://www.google.com/url?q=https://onsiteenergyinc.com/bcorp&source=gmail-html&ust=1677085494759000&usg=AOvVaw0EluC1lXtz2KlRFag-htKe" rel="noreferrer noreferrer" style="border:none" target="_blank"><img src="https://i.postimg.cc/2y1LtFnM/email-bcorp.png" alt="B Corporation" width="22" height="33" align="bottom" hspace="2" vspace="2" style="display:block"></a></td></tr></tbody></table></td></tr></tbody></table></div></div></div></div></div></div><div></div></div>
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