Reference for Eruvin 68:13
<big><strong>מתני׳</strong></big> נתנו במגדל ואבד המפתח הרי זה עירוב ר"א אומר אם אינו יודע שהמפתח במקומו אינו עירוב:
Is not this a case where he<span class="x" onmousemove="('comment',' The man for whom the 'erub was prepared.');"><sup>37</sup></span> is in one place and his 'erub is in another?<span class="x" onmousemove="('comment',' Since the man cannot get at the 'erub without a key.');"><sup>38</sup></span> - Both Rab and Samuel explained: We are dealing here with a CUPBOARD of bricks<span class="x" onmousemove="('comment',' Which can easily be broken into (as will be explained infra) .');"><sup>39</sup></span> and this ruling represents the view of R'Meir who maintains that it is permitted at the outset<span class="x" onmousemove="('comment',' Even on a day when mukzeh (v. Glos.) is forbidden.');"><sup>40</sup></span>