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CBU Mailboxes FAQ

How are CBU cluster mailboxes mounted?

CBU cluster mailboxes can only be mounted on a pedestal and cannot be attached to a wall. NOTE: Installing your CBU mailbox on any pedestal or surface other than the factory-supplied pedestal can void your limited manufacturer’s warranty.

Can you put outgoing mail in a cluster mailbox?

Yes, cluster mailboxes can be ordered with an outgoing mail slot.

Do cluster mailboxes come with a parcel locker?

Yes, by regulation, all cluster mailboxes with 10 or more mailbox units must also include a minimum of one parcel locker.

How secure are CBU mailboxes?

USPS-approved CBU mailboxes are robotically welded, high security, tamper-proof commercial mailboxes made from industrial-grade aluminum. They are also weatherproof and come with tamper-proof heavy-duty cam locks.

Do cluster mailboxes come with installation instructions?

Yes, cluster mailbox installation instructions are available through the MailboxWorks. If you still have questions about cluster mailbox installation, please email customer care.

Do you carry cluster mailbox replacement parts?

Yes, you can order cluster mailbox replacement parts on our Mailbox Replacement Parts page.

Do I need to buy my own anchor bolts?

Yes. Since installations may vary, anchor bolts are not supplied as per USPS regulations.

Can the parcel locker be used as a tenant mailbox?

No. USPS does not allow parcel lockers to be used for any other purpose. The removal, conversion, or modification of CBU parcel lockers is strictly prohibited.

Can I change the configuration on my F-series cluster mailboxes?

No, USPS does not allow any modifications to the commercial CBU mailbox configuration in any way.

Do you carry CBU mailboxes for private mail delivery?

Yes. The CBU commercial mailboxes we carry can be used for private mail delivery service and would require that you buy your own parcel locker and master door conversion locks.

Do you sell used CBU cluster mailboxes?

No. We only sell new CBU mailboxes.

Can I mount the CBU on an existing pedestal?

We do NOT recommend this. Old or used pedestals may not be as strong or may have corrosion issues, which could cause the CBU to collapse. The height of the existing pedestal may also be incorrect, in which case the USPS may decline to deliver mail to the unit. The CBU itself can weigh up to 150lbs and needs to be properly supported. Using an old pedestal can cause potential danger to your USPS mail carrier and tenants.

Can I mount the CBU mailbox on a pedestal other than the factory-supplied pedestal?

We do NOT recommend this. The pedestals that come with CBUs are specifically designed to support the cluster box unit. Should you decide to use a different mounting method or pedestal (other than the factory-supplied CBU pedestal and instructions), you will need to obtain approval from your local USPS postmaster.

Can I adjust the height of the CBU mailbox during installation?

No. CBUs must be installed at the exact height requirements as specified by the USPS.

Do I need to contact my local USPS before installing a cluster box unit?

Yes. Contact your local postal officials before installing, as the USPS may need to determine its placement.

Does my CBU mailbox come with everything needed for installation and usage?

Based on USPS requirements/requests, there are two additional items required for your CBU gang mailboxes that are not included with your purchase:
1. USPS Arrow Locks – These *are* supplied by USPS directly and are installed on the outgoing mailbox door and parcel locker doors. The USPS does not allow factories or any non-USPS employees to possess these master locks. Once you have your cluster box unit installed, you will need to contact your local USPS to request that they come and install the USPS Arrow Locks. Typically, they do not charge for this service.
2. Anchor Bolts – Used for mounting the CBU mailbox to concrete, which requires four bolts per unit. USPS requests that mailbox distributors do *not* include concrete anchor bolts because there is too much variation in each individual installation. Please refer to our CBU Installation Instructions to determine the anchor bolts required for your mailbox installation. The factory recommends that you use 1/2-inch diameter L-Bolts and a range of expansion anchor bolts outlined in the instructions. For most applications, you can purchase the L-bolt anchor bolt kit or any expansion anchor bolts from us as well.

I cannot find the tenant keys or mounting hardware or installation instructions for my new CBU.

You should find all the keys, mounting hardware, and instructions tucked carefully inside the mailbox cabinet. In order to access these, you need to take the cluster mailbox module out of the box and set it on a workbench. Second, open the outgoing mailbox door located below the outgoing mail slot on the right side. Third, push up on the latch on the left side of the inside of the outgoing mailbox compartment. Finally, the right side of the CBU cabinet will open and there will be a latch on the left side of the cabinet to open completely. You will find all the keys, hardware, and instructions in the lower left-hand side compartment.

Why is there no lock on the CBU outgoing mailbox?

By regulation, USPS must install these master locks, which are called “Arrow Locks.”

What is a parcel locker?

The parcel locker is a component of the CBU that allows for the delivery of larger parcels for your tenants.

How do you open a parcel locker?

1. The USPS mail carrier places the package inside a parcel locker.
2. The mail carrier then places a corresponding key and instructions in the tenant’s regular mailbox.
3. The tenant receives the parcel locker key and instructions from their own mailbox.
4. The tenant inserts the key into the parcel locker to retrieve the package. The key remains in the lock and only the postal carrier can remove it.

What is a captive lock?

Parcel lockers have a “captive lock,” which means that once the key is inserted into the lock, it cannot be removed. Only a USPS mail carrier will be able to remove it on their next visit.

Do mailbox locks come installed in the CBU mailboxes upon delivery?

Yes. All cluster mailbox locks come with locks installed and with three keys for each tenant mailbox lock.

Can I get more than just three keys for a tenant door?

You can order up to six keys per tenant door if you need more than the standard three keys that come with the CBU mailbox unit. Please contact our customer service team to discuss this option.

How do I order additional tenant keys after purchasing at CBU?

Contact us to purchase key blanks that you can take to any locksmith or hardware store to have cut. Please note that the locks and key blanks on all CBU mailboxes are proprietary and are difficult to source through hardware stores and locksmiths. We would be happy to source these for you!

When ordering, please have the original key(s) available as there are two key blank types used by the manufacturer. You will find a four-digit number on the key followed by “PS”. Typically, Florence Mailboxes will use the same key blank for the CBU, but it is not always possible, especially for larger orders. Please check each key before ordering any key blanks.

Can I order new locks for tenant mailbox doors?

Yes. There are several reasons you may want to do this. A tenant may move out, or you may have keys for a lock that are lost or stolen. If you need to order new locks for your CBUs, please contact us.

The outgoing mailbox door on my CBU mailbox doesn’t have a lock. What should I do?

This USPS Arrow Lock can only be installed by the USPS upon your request. Please contact USPS for installation. Typically, they do not charge for this service.

How are CBUs shipped?

All CBUs (regardless of model number or number of doors) ship directly from the manufacturer in two boxes. The one box contains the pedestal which is about 25 pounds. The other box contains the CBU mailbox model, which ranges from 100-150 pounds depending on the unit size. Any decorative components such as a roof, cap, or pedestal cover will ship in additional boxes. We recommend that upon delivery, you confirm you have received the right number of shipping boxes.

What if one of my CBU parcels or boxes appears to be damaged upon delivery?

Carefully inspect and report any damaged shipping boxes to the delivery person before signing for the delivery of goods. If you notice significant damage, you can refuse delivery of the item. Please note that we only recommend refusing delivery of the damaged items and not the entire shipment. Should this happen, please contact us as soon as possible.

What if I notice damage to shipping boxes after the delivery person has left?

In this case, please contact us as soon as possible. We recommend taking pictures to document the damage for the factory and delivery company’s records. Please note that we can best address an issue if you alert us right away.

Can I install a digital combination lock on the CBU?

No. Combination locks cannot be installed for private mail distribution in settings like a college, university, or office. We offer several alternative community mailboxes and multi-mailbox units with combination locks.

Can I buy a sign holder to attach to the CBU cluster mailbox?

We have been asked if we sell plexiglass sign holders to attach to the CBU and house various notices. Unfortunately, we do not sell these.

Can I get a CBU cluster mailbox with more or fewer doors than the standard number of door units?

Yes. You would be looking at our 4C pedestal mailboxes that can range from 1-29 tenant doors, with a variety of configurations. Please note that these require USPS approval prior to purchasing.

Are there rear-loading cluster mailbox units that open from the back?

No. The rear-loading BUs are not available.

Can I buy a high-security CBU mailbox?

High-security CBU mailboxes have been discontinued because most of these security features have been incorporated into the current standard CBU mailboxes on the market.